diff --git a/src/db/db/dbConverters.h b/src/db/db/dbConverters.h
index 2403f6c21..3da99c447 100644
--- a/src/db/db/dbConverters.h
+++ b/src/db/db/dbConverters.h
@@ -40,6 +40,8 @@ namespace db
 template <class T>
 struct DB_PUBLIC_TEMPLATE TransformationConverter
 {
+  typedef T value_type;
+
   std::string to_string (const T &t) const
   {
     return t.to_string ();
@@ -58,6 +60,8 @@ struct DB_PUBLIC_TEMPLATE TransformationConverter
  */
 struct DB_PUBLIC LayoutLayerConverter
 {
+  typedef db::LayerProperties value_type;
+
   std::string to_string (const db::LayerProperties &p) const
   {
     return p.to_string ();
@@ -79,6 +83,8 @@ struct DB_PUBLIC LayoutLayerConverter
 template <class P>
 struct DB_PUBLIC_TEMPLATE PointConverter
 {
+  typedef P value_type;
+
   std::string to_string (const P &p) const
   {
     return tl::to_string (p.x ()) + "," + tl::to_string (p.y ());
diff --git a/src/db/db/dbStream.h b/src/db/db/dbStream.h
index ace7531aa..88a30fbf5 100644
--- a/src/db/db/dbStream.h
+++ b/src/db/db/dbStream.h
@@ -154,7 +154,7 @@ class StreamOptionsReadAdaptor
 {
 public:
   typedef tl::pass_by_ref_tag tag;
-  typedef tl::pb_zero_cardinality_tag cardinality;
+  typedef tl::zero_cardinality_tag cardinality;
 
   StreamOptionsReadAdaptor ()
     : mp_options (0), m_done (false)
diff --git a/src/db/db/dbTechnology.h b/src/db/db/dbTechnology.h
index 2fa1c6f5e..9477a18cd 100644
--- a/src/db/db/dbTechnology.h
+++ b/src/db/db/dbTechnology.h
@@ -807,6 +807,7 @@ class TechnologyComponentReadAdaptor
 {
 public:
   typedef tl::pass_by_ref_tag tag;
+  typedef tl::single_cardinality_tag cardinality;
 
   TechnologyComponentReadAdaptor (const std::string &name)
     : m_name (name), mp_t (0), m_done (false)
diff --git a/src/img/img/imgStream.cc b/src/img/img/imgStream.cc
index 4f6833aca..5de8bdddc 100644
--- a/src/img/img/imgStream.cc
+++ b/src/img/img/imgStream.cc
@@ -359,6 +359,8 @@ namespace {
 
   struct PointConverter
   {
+    typedef db::DPoint value_type;
+
     std::string to_string (const db::DPoint &p) const
     {
       return p.to_string ();
@@ -373,6 +375,8 @@ namespace {
 
   struct ColorMapConverter
   {
+    typedef std::pair<double, std::pair<tl::Color, tl::Color> > value_type;
+
     std::string to_string (const std::pair<double, std::pair<tl::Color, tl::Color> > &cm) const
     {
       std::string s;
@@ -427,7 +431,7 @@ tl::XMLStruct<ImageProxy> s_img_structure ("image-data",
   tl::make_member (&ImageProxy::max_value, &ImageProxy::set_max_value, "max-value") +
   tl::make_element (&ImageProxy::data_mapping, &ImageProxy::set_data_mapping, "data-mapping",
     tl::make_element (&img::DataMapping::false_color_nodes, "color-map",
-      tl::make_member<std::pair<double, std::pair<tl::Color, tl::Color> >, img::DataMapping::false_color_nodes_type::const_iterator, img::DataMapping::false_color_nodes_type, ColorMapConverter> (&img::DataMapping::false_color_nodes_type::begin, &img::DataMapping::false_color_nodes_type::end, &img::DataMapping::false_color_nodes_type::push_back, "color-map-entry", ColorMapConverter ())
+      tl::make_member<std::pair<double, std::pair<tl::Color, tl::Color> >, img::DataMapping::false_color_nodes_type::const_iterator, img::DataMapping::false_color_nodes_type, tl::XMLStringBasedConverter<ColorMapConverter> > (&img::DataMapping::false_color_nodes_type::begin, &img::DataMapping::false_color_nodes_type::end, &img::DataMapping::false_color_nodes_type::push_back, "color-map-entry", tl::XMLStringBasedConverter<ColorMapConverter> ())
     ) +
     tl::make_member (&img::DataMapping::brightness, "brightness") +
     tl::make_member (&img::DataMapping::contrast, "contrast") +
@@ -437,7 +441,7 @@ tl::XMLStruct<ImageProxy> s_img_structure ("image-data",
     tl::make_member (&img::DataMapping::blue_gain, "blue-gain")
   ) +
   tl::make_element (&ImageProxy::landmarks, &ImageProxy::set_landmarks, "landmarks",
-    tl::make_member<db::DPoint, img::Object::landmarks_type::const_iterator, img::Object::landmarks_type, PointConverter> (&img::Object::landmarks_type::begin, &img::Object::landmarks_type::end, &img::Object::landmarks_type::push_back, "landmark", PointConverter ())
+    tl::make_member<db::DPoint, img::Object::landmarks_type::const_iterator, img::Object::landmarks_type, tl::XMLStringBasedConverter<PointConverter> > (&img::Object::landmarks_type::begin, &img::Object::landmarks_type::end, &img::Object::landmarks_type::push_back, "landmark", tl::XMLStringBasedConverter<PointConverter> ())
   ) +
   tl::make_member (&ImageProxy::begin_byte_data, &ImageProxy::end_byte_data, &ImageProxy::push_byte_data, "byte-data") +
   tl::make_member (&ImageProxy::begin_data, &ImageProxy::end_data, &ImageProxy::push_data, "data")
diff --git a/src/lay/lay/laySaltGrain.cc b/src/lay/lay/laySaltGrain.cc
index f9c3cb181..ff06fdb2b 100644
--- a/src/lay/lay/laySaltGrain.cc
+++ b/src/lay/lay/laySaltGrain.cc
@@ -353,6 +353,8 @@ SaltGrain::valid_version (const std::string &v)
 
 struct TimeConverter
 {
+  typedef QDateTime value_type;
+
   std::string to_string (const QDateTime &time) const
   {
     if (time.isNull ()) {
@@ -374,6 +376,8 @@ struct TimeConverter
 
 struct ImageConverter
 {
+  typedef QImage value_type;
+
   std::string to_string (const QImage &image) const
   {
     if (image.isNull ()) {
@@ -416,10 +420,10 @@ SaltGrain::xml_elements ()
       tl::make_member (&SaltGrain::license, &SaltGrain::set_license, "license") +
       tl::make_member (&SaltGrain::author, &SaltGrain::set_author, "author") +
       tl::make_member (&SaltGrain::author_contact, &SaltGrain::set_author_contact, "author-contact") +
-      tl::make_member (&SaltGrain::authored_time, &SaltGrain::set_authored_time, "authored-time", TimeConverter ()) +
-      tl::make_member (&SaltGrain::installed_time, &SaltGrain::set_installed_time, "installed-time", TimeConverter ()) +
-      tl::make_member (&SaltGrain::icon, &SaltGrain::set_icon, "icon", ImageConverter ()) +
-      tl::make_member (&SaltGrain::screenshot, &SaltGrain::set_screenshot, "screenshot", ImageConverter ()) +
+      tl::make_member (&SaltGrain::authored_time, &SaltGrain::set_authored_time, "authored-time", tl::XMLStringBasedConverter<TimeConverter> ()) +
+      tl::make_member (&SaltGrain::installed_time, &SaltGrain::set_installed_time, "installed-time", tl::XMLStringBasedConverter<TimeConverter> ()) +
+      tl::make_member (&SaltGrain::icon, &SaltGrain::set_icon, "icon",  tl::XMLStringBasedConverter<ImageConverter> ()) +
+      tl::make_member (&SaltGrain::screenshot, &SaltGrain::set_screenshot, "screenshot", tl::XMLStringBasedConverter<ImageConverter> ()) +
       tl::make_element (&SaltGrain::begin_dependencies, &SaltGrain::end_dependencies, &SaltGrain::add_dependency, "depends",
         tl::make_member (&SaltGrainDependency::name, "name") +
         tl::make_member (&SaltGrainDependency::url, "url") +
diff --git a/src/laybasic/laybasic/layDispatcher.cc b/src/laybasic/laybasic/layDispatcher.cc
index 5422c4ab0..91455a406 100644
--- a/src/laybasic/laybasic/layDispatcher.cc
+++ b/src/laybasic/laybasic/layDispatcher.cc
@@ -108,6 +108,8 @@ Dispatcher::config_finalize ()
 
 struct ConfigGetAdaptor
 {
+  typedef tl::zero_cardinality_tag cardinality;
+
   ConfigGetAdaptor (const std::string &name)
     : mp_owner (0), m_done (false), m_name (name)
   {
@@ -145,6 +147,8 @@ private:
 
 struct ConfigGetNullAdaptor
 {
+  typedef tl::zero_cardinality_tag cardinality;
+
   ConfigGetNullAdaptor ()
   {
     // .. nothing yet ..
diff --git a/src/lym/lym/lymMacro.cc b/src/lym/lym/lymMacro.cc
index 7c239a757..de0004a3a 100644
--- a/src/lym/lym/lymMacro.cc
+++ b/src/lym/lym/lymMacro.cc
@@ -150,6 +150,8 @@ bool Macro::del ()
 
 struct Interpreter2s
 {
+  typedef Macro::Interpreter value_type;
+
   std::string to_string (Macro::Interpreter i) const
   {
     switch (i) {
@@ -199,7 +201,7 @@ static tl::XMLStruct<lym::Macro> xml_struct ("klayout-macro",
   tl::make_member (&Macro::show_in_menu, &Macro::set_show_in_menu, "show-in-menu") +
   tl::make_member (&Macro::group_name, &Macro::set_group_name, "group-name") +
   tl::make_member (&Macro::menu_path, &Macro::set_menu_path, "menu-path") +
-  tl::make_member (&Macro::interpreter, &Macro::set_interpreter, "interpreter", Interpreter2s ()) +
+  tl::make_member (&Macro::interpreter, &Macro::set_interpreter, "interpreter", tl::XMLStringBasedConverter<Interpreter2s> ()) +
   tl::make_member (&Macro::dsl_interpreter, &Macro::set_dsl_interpreter, "dsl-interpreter-name") +
   tl::make_member (&Macro::text, &Macro::set_text, "text") +
   tl::make_member<Macro> ("format")  //  for backward compatibility
diff --git a/src/plugins/streamers/pcb/db_plugin/dbGerberImportData.cc b/src/plugins/streamers/pcb/db_plugin/dbGerberImportData.cc
index 00b04b164..608090f3c 100644
--- a/src/plugins/streamers/pcb/db_plugin/dbGerberImportData.cc
+++ b/src/plugins/streamers/pcb/db_plugin/dbGerberImportData.cc
@@ -166,6 +166,8 @@ GerberImportData::setup_importer (db::GerberImporter *importer)
 
 struct MountingConverter
 {
+  typedef GerberImportData::mounting_type value_type;
+
   std::string to_string (GerberImportData::mounting_type m) const
   {
     return m == GerberImportData::MountingTop ? "top" : "bottom";
@@ -190,9 +192,9 @@ pcb_project_structure ("pcb-project",
   tl::make_member (&GerberImportData::border, "border") +
   tl::make_member (&GerberImportData::free_layer_mapping, "free-layer-mapping") +
   tl::make_element (&GerberImportData::layout_layers, "layout-layers",
-    tl::make_member<db::LayerProperties, std::vector<db::LayerProperties>::const_iterator, std::vector<db::LayerProperties> > (&std::vector<db::LayerProperties>::begin, &std::vector<db::LayerProperties>::end, &std::vector<db::LayerProperties>::push_back, "layout-layer", db::LayoutLayerConverter ())
+    tl::make_member<db::LayerProperties, std::vector<db::LayerProperties>::const_iterator, std::vector<db::LayerProperties> > (&std::vector<db::LayerProperties>::begin, &std::vector<db::LayerProperties>::end, &std::vector<db::LayerProperties>::push_back, "layout-layer", tl::XMLStringBasedConverter<db::LayoutLayerConverter> ())
   ) +
-  tl::make_member (&GerberImportData::mounting, "mounting", MountingConverter ()) +
+  tl::make_member (&GerberImportData::mounting, "mounting", tl::XMLStringBasedConverter<MountingConverter> ()) +
   tl::make_member (&GerberImportData::num_metal_layers, "num-metal-layers") +
   tl::make_member (&GerberImportData::num_via_types, "num-via-types") +
   tl::make_element (&GerberImportData::artwork_files, "artwork-files",
@@ -217,11 +219,11 @@ pcb_project_structure ("pcb-project",
   ) +
   tl::make_element (&GerberImportData::reference_points, "reference-points",
     tl::make_element<std::pair <db::DPoint, db::DPoint>, std::vector<std::pair <db::DPoint, db::DPoint> >::const_iterator, std::vector<std::pair <db::DPoint, db::DPoint> > > (&std::vector<std::pair <db::DPoint, db::DPoint> >::begin, &std::vector<std::pair <db::DPoint, db::DPoint> >::end, &std::vector<std::pair <db::DPoint, db::DPoint> >::push_back, "reference-point",
-      tl::make_member (&std::pair <db::DPoint, db::DPoint>::first, "pcb", db::PointConverter<db::DPoint> ()) +
-      tl::make_member (&std::pair <db::DPoint, db::DPoint>::second, "layout", db::PointConverter<db::DPoint> ())
+      tl::make_member (&std::pair <db::DPoint, db::DPoint>::first, "pcb", tl::XMLStringBasedConverter<db::PointConverter<db::DPoint> > ()) +
+      tl::make_member (&std::pair <db::DPoint, db::DPoint>::second, "layout", tl::XMLStringBasedConverter<db::PointConverter<db::DPoint> > ())
     )
   ) +
-  tl::make_member (&GerberImportData::explicit_trans, "explicit-trans", db::TransformationConverter<db::DCplxTrans> ()) +
+  tl::make_member (&GerberImportData::explicit_trans, "explicit-trans", tl::XMLStringBasedConverter<db::TransformationConverter<db::DCplxTrans> > ()) +
   tl::make_member (&GerberImportData::layer_properties_file, "layer-properties-file") +
   tl::make_member (&GerberImportData::num_circle_points, "num-circle-points") +
   tl::make_member (&GerberImportData::merge_flag, "merge-flag") +
diff --git a/src/plugins/tools/import/lay_plugin/layStreamImportDialog.cc b/src/plugins/tools/import/lay_plugin/layStreamImportDialog.cc
index 3f5e7841d..a3c56853c 100644
--- a/src/plugins/tools/import/lay_plugin/layStreamImportDialog.cc
+++ b/src/plugins/tools/import/lay_plugin/layStreamImportDialog.cc
@@ -49,6 +49,8 @@ static struct {
 
 struct ModeConverter
 {
+  typedef lay::StreamImportData::mode_type value_type;
+
   std::string to_string (lay::StreamImportData::mode_type t) const
   {
     for (unsigned int i = 0; i < sizeof (mode_strings) / sizeof (mode_strings [0]); ++i) {
@@ -82,6 +84,8 @@ static struct {
 
 struct LayerModeConverter
 {
+  typedef lay::StreamImportData::layer_mode_type value_type;
+
   std::string to_string (lay::StreamImportData::layer_mode_type t) const
   {
     for (unsigned int i = 0; i < sizeof (layer_mode_strings) / sizeof (layer_mode_strings [0]); ++i) {
@@ -144,8 +148,8 @@ static tl::XMLElementList xml_elements ()
     ) +
     tl::make_member (&StreamImportData::topcell, "cell-name") +
     tl::make_member (&StreamImportData::layer_offset, "layer-offset") +
-    tl::make_member (&StreamImportData::layer_mode, "layer-mode", LayerModeConverter ()) +
-    tl::make_member (&StreamImportData::mode, "import-mode", ModeConverter ()) +
+    tl::make_member (&StreamImportData::layer_mode, "layer-mode", tl::XMLStringBasedConverter<LayerModeConverter> ()) +
+    tl::make_member (&StreamImportData::mode, "import-mode", tl::XMLStringBasedConverter<ModeConverter> ()) +
     tl::make_element (&StreamImportData::reference_points, "reference-points",
       tl::make_element<ref_point, ref_point_v::const_iterator, ref_point_v> (&ref_point_v::begin, &ref_point_v::end, &ref_point_v::push_back, "reference-point",
         tl::make_member (&ref_point::first, "p1") +
diff --git a/src/plugins/tools/net_tracer/db_plugin/dbNetTracerPlugin.cc b/src/plugins/tools/net_tracer/db_plugin/dbNetTracerPlugin.cc
index 1967f7bb0..ce45a45ac 100644
--- a/src/plugins/tools/net_tracer/db_plugin/dbNetTracerPlugin.cc
+++ b/src/plugins/tools/net_tracer/db_plugin/dbNetTracerPlugin.cc
@@ -24,50 +24,49 @@
 #include "dbTechnology.h"
 #include "tlClassRegistry.h"
 
-namespace tl
-{
-  /**
-   *  @brief A specialization of the XMLConverter that is used to serialize the connection info
-   */
-
-  template <>
-  struct XMLStdConverter<db::NetTracerConnectionInfo>
-  {
-    std::string to_string (const db::NetTracerConnectionInfo &v) const
-    {
-      return v.to_string ();
-    }
-
-    void from_string (const std::string &s, db::NetTracerConnectionInfo &v) const
-    {
-      tl::Extractor ex (s.c_str ());
-      v.parse (ex);
-    }
-  };
-
-  /**
-   *  @brief A specialization of the XMLConverter that is used to serialize the symbol info
-   */
-
-  template <>
-  struct XMLStdConverter<db::NetTracerSymbolInfo>
-  {
-    std::string to_string (const db::NetTracerSymbolInfo &v) const
-    {
-      return v.to_string ();
-    }
-
-    void from_string (const std::string &s, db::NetTracerSymbolInfo &v) const
-    {
-      tl::Extractor ex (s.c_str ());
-      v.parse (ex);
-    }
-  };
-}
-
 namespace
 {
 
+/**
+ *  @brief A string converter for NetTracerConnectionInfo
+ */
+
+struct NetTracerConnectionInfoConverter
+{
+  typedef db::NetTracerConnectionInfo value_type;
+
+  std::string to_string (const db::NetTracerConnectionInfo &v) const
+  {
+    return v.to_string ();
+  }
+
+  void from_string (const std::string &s, db::NetTracerConnectionInfo &v) const
+  {
+    tl::Extractor ex (s.c_str ());
+    v.parse (ex);
+  }
+};
+
+/**
+ *  @brief A specialization of the XMLConverter that is used to serialize the symbol info
+ */
+
+struct NetTracerSymbolInfoConverter
+{
+  typedef db::NetTracerSymbolInfo value_type;
+
+  std::string to_string (const db::NetTracerSymbolInfo &v) const
+  {
+    return v.to_string ();
+  }
+
+  void from_string (const std::string &s, db::NetTracerSymbolInfo &v) const
+  {
+    tl::Extractor ex (s.c_str ());
+    v.parse (ex);
+  }
+};
+
 static const db::NetTracerConnectivity *
 get_fallback_default (const db::NetTracerTechnologyComponent &tc)
 {
@@ -129,6 +128,7 @@ template <class Value, class Iter>
 struct FallbackXMLReadAdaptor
 {
   typedef tl::pass_by_ref_tag tag;
+  typedef tl::many_cardinality_tag cardinality;
 
   FallbackXMLReadAdaptor (Iter (db::NetTracerConnectivity::*begin) () const, Iter (db::NetTracerConnectivity::*end) () const)
     : mp_begin (begin), mp_end (end)
@@ -195,10 +195,10 @@ public:
         tl::make_member ((NetTracerConnectivity::const_symbol_iterator (NetTracerConnectivity::*) () const) &NetTracerConnectivity::begin_symbols, (NetTracerConnectivity::const_symbol_iterator (NetTracerConnectivity::*) () const) &NetTracerConnectivity::end_symbols, &NetTracerConnectivity::add_symbol, "symbols")
       ) +
       //  Fallback readers for migrating pre-0.28 setups to 0.28 and backward compatibility
-      tl::XMLMember<NetTracerConnectionInfo, NetTracerTechnologyComponent, FallbackXMLReadAdaptor <NetTracerConnectionInfo, NetTracerConnectivity::const_iterator>, FallbackXMLWriteAdaptor <NetTracerConnectionInfo>, tl::XMLStdConverter <NetTracerConnectionInfo> > (
+      tl::XMLMember<NetTracerConnectionInfo, NetTracerTechnologyComponent, FallbackXMLReadAdaptor <NetTracerConnectionInfo, NetTracerConnectivity::const_iterator>, FallbackXMLWriteAdaptor <NetTracerConnectionInfo>, tl::XMLStringBasedConverter <NetTracerConnectionInfoConverter> > (
         FallbackXMLReadAdaptor <NetTracerConnectionInfo, NetTracerConnectivity::const_iterator> (&NetTracerConnectivity::begin, &NetTracerConnectivity::end),
         FallbackXMLWriteAdaptor <NetTracerConnectionInfo> (&NetTracerConnectivity::add), "connection") +
-      tl::XMLMember<NetTracerSymbolInfo, NetTracerTechnologyComponent, FallbackXMLReadAdaptor <NetTracerSymbolInfo, NetTracerConnectivity::const_symbol_iterator>, FallbackXMLWriteAdaptor <NetTracerSymbolInfo>, tl::XMLStdConverter <NetTracerSymbolInfo> > (
+      tl::XMLMember<NetTracerSymbolInfo, NetTracerTechnologyComponent, FallbackXMLReadAdaptor <NetTracerSymbolInfo, NetTracerConnectivity::const_symbol_iterator>, FallbackXMLWriteAdaptor <NetTracerSymbolInfo>, tl::XMLStringBasedConverter <NetTracerSymbolInfoConverter> > (
         FallbackXMLReadAdaptor <NetTracerSymbolInfo, NetTracerConnectivity::const_symbol_iterator> (&NetTracerConnectivity::begin_symbols, &NetTracerConnectivity::end_symbols),
         FallbackXMLWriteAdaptor <NetTracerSymbolInfo> (&NetTracerConnectivity::add_symbol), "symbols")
     );
diff --git a/src/rdb/rdb/rdbFile.cc b/src/rdb/rdb/rdbFile.cc
index e6159b6a4..dc533bf7f 100644
--- a/src/rdb/rdb/rdbFile.cc
+++ b/src/rdb/rdb/rdbFile.cc
@@ -38,6 +38,8 @@ namespace rdb
 
 struct ValueConverter
 {
+  typedef std::string pb_type;
+
   ValueConverter (rdb::Database *rdb)
     : mp_rdb (rdb)
   {
@@ -53,6 +55,16 @@ struct ValueConverter
     value.from_string (mp_rdb, s);
   }
 
+  std::string pb_encode (const ValueWrapper &value) const
+  {
+    return value.to_string (mp_rdb);
+  }
+
+  void pb_decode (const std::string &s, ValueWrapper &value) const
+  {
+    value.from_string (mp_rdb, s);
+  }
+
 private:
   rdb::Database *mp_rdb;
 };
@@ -110,7 +122,7 @@ make_rdb_structure (rdb::Database *rdb)
         tl::make_member<std::string, rdb::Item> (&rdb::Item::comment, &rdb::Item::set_comment, "comment") +
         tl::make_member<std::string, rdb::Item> (&rdb::Item::image_str, &rdb::Item::set_image_str, "image") +
         tl::make_element<rdb::Values, rdb::Item> (&rdb::Item::values, &rdb::Item::set_values, "values", 
-          tl::make_member<rdb::ValueWrapper, rdb::Values::const_iterator, rdb::Values> (&rdb::Values::begin, &rdb::Values::end, &rdb::Values::add, "value", ValueConverter (rdb)) 
+          tl::make_member<rdb::ValueWrapper, rdb::Values::const_iterator, rdb::Values> (&rdb::Values::begin, &rdb::Values::end, &rdb::Values::add, "value", ValueConverter (rdb))
         )
       )
     )
diff --git a/src/tl/tl/tlXMLParser.h b/src/tl/tl/tlXMLParser.h
index 7efb7c585..f8d73d5b3 100644
--- a/src/tl/tl/tlXMLParser.h
+++ b/src/tl/tl/tlXMLParser.h
@@ -62,16 +62,16 @@ struct pass_by_ref_tag {
   pass_by_ref_tag () { } 
 };
 
-struct pb_zero_cardinality_tag {
-  pb_zero_cardinality_tag () { }
+struct zero_cardinality_tag {
+  zero_cardinality_tag () { }
 };
 
-struct pb_single_cardinality_tag {
-  pb_single_cardinality_tag () { }
+struct single_cardinality_tag {
+  single_cardinality_tag () { }
 };
 
-struct pb_many_cardinality_tag {
-  pb_many_cardinality_tag () { }
+struct many_cardinality_tag {
+  many_cardinality_tag () { }
 };
 
 /**
@@ -570,17 +570,17 @@ protected:
 
   std::string make_message_name () const;
 
-  static Cardinality get_cardinality (tl::pb_zero_cardinality_tag)
+  static Cardinality get_cardinality (tl::zero_cardinality_tag)
   {
     return Zero;
   }
 
-  static Cardinality get_cardinality (tl::pb_single_cardinality_tag)
+  static Cardinality get_cardinality (tl::single_cardinality_tag)
   {
     return Single;
   }
 
-  static Cardinality get_cardinality (tl::pb_many_cardinality_tag)
+  static Cardinality get_cardinality (tl::many_cardinality_tag)
   {
     return Many;
   }
@@ -593,69 +593,37 @@ private:
 };
 
 /**
- *  @brief A XML child element 
- *
- *  This class is a XML structure component describing a child
- *  element in the XML tree. There is no limit about the number of
- *  child elements. 
- *  This object must be provided a pointer to a factory method (in
- *  the parent's class), a name and a list of children (which can be
- *  empty).
- *  Write is a class providing a Obj &operator(Parent &) operator.
- *  It is supposed to create a new instance of Obj within Parent.
- *  Read is a class providing a start(const Parent &) method to start 
- *  iterating over the instances, a const Obj &operator() const for 
- *  access and a bool at_end() method to determine if the iterator
- *  is at the end and next() to increment the iterator.
+ *  @brief Basic implementation for XMLElement and XMLElementWithParentRef
  */
 
 template <class Obj, class Parent, class Read, class Write>
-class TL_PUBLIC_TEMPLATE XMLElement
+class TL_PUBLIC_TEMPLATE XMLElementImplBase
   : public XMLElementBase
 {
 public:
-  XMLElement (const Read &r, const Write &w, const std::string &name, const XMLElementList &children)
+  XMLElementImplBase (const Read &r, const Write &w, const std::string &name, const XMLElementList &children)
     : XMLElementBase (name, children), m_r (r), m_w (w)
   {
     // .. nothing yet ..
   }
 
-  XMLElement (const Read &r, const Write &w, const std::string &name, const XMLElementList *children)
+  XMLElementImplBase (const Read &r, const Write &w, const std::string &name, const XMLElementList *children)
     : XMLElementBase (name, children), m_r (r), m_w (w)
   {
     // .. nothing yet ..
   }
 
-  XMLElement (const XMLElement<Obj, Parent, Read, Write> &d)
+  XMLElementImplBase (const XMLElementImplBase<Obj, Parent, Read, Write> &d)
     : XMLElementBase (d), m_r (d.m_r), m_w (d.m_w)
   {
     // .. nothing yet ..
   }
 
-  virtual XMLElementBase *clone () const
-  {
-    return new XMLElement<Obj, Parent, Read, Write> (*this);
-  }
-
-  virtual void create (const XMLElementBase *, XMLReaderState &objs, const std::string & /*uri*/, const std::string & /*lname*/, const std::string & /*qname*/) const
-  {
-    XMLObjTag<Obj> tag;
-    objs.push (tag);
-  }
-
   virtual void cdata (const std::string & /*cdata*/, XMLReaderState & /*objs*/) const
   {
     // .. nothing yet ..
   }
 
-  virtual void finish (const XMLElementBase * /*parent*/, XMLReaderState &objs, const std::string & /*uri*/, const std::string & /*lname*/, const std::string & /*qname*/) const
-  {
-    XMLObjTag<Obj> tag;
-    XMLObjTag<Parent> parent_tag;
-    m_w (*objs.parent (parent_tag), objs);
-    objs.pop (tag);
-  }
-
   virtual void write (const XMLElementBase * /*parent*/, tl::OutputStream &os, int indent, XMLWriterState &objs) const
   {
     XMLObjTag<Parent> parent_tag;
@@ -673,7 +641,7 @@ public:
     }
   }
 
-  virtual bool has_any (XMLWriterState &objs) const 
+  virtual bool has_any (XMLWriterState &objs) const
   {
     XMLObjTag<Parent> parent_tag;
     Read r (m_r);
@@ -681,20 +649,6 @@ public:
     return (! r.at_end ());
   }
 
-  virtual void pb_create (const XMLElementBase *, XMLReaderState &objs) const
-  {
-    XMLObjTag<Obj> tag;
-    objs.push (tag);
-  }
-
-  virtual void pb_finish (const XMLElementBase * /*parent*/, XMLReaderState &objs) const
-  {
-    XMLObjTag<Obj> tag;
-    XMLObjTag<Parent> parent_tag;
-    m_w (*objs.parent (parent_tag), objs);
-    objs.pop (tag);
-  }
-
   virtual void pb_parse (PBParser *parser, tl::ProtocolBufferReaderBase &reader) const
   {
     reader.open ();
@@ -739,10 +693,11 @@ public:
     }
   }
 
-private:
+protected:
   Read m_r;
   Write m_w;
 
+private:
   //  this write helper is used if the reader delivers an object by value
   void write_obj (Obj obj, tl::OutputStream &os, int indent, tl::pass_by_value_tag, XMLWriterState &objs) const
   {
@@ -773,7 +728,7 @@ private:
       writer.begin_seq (tag, pass == 0);
       objs.push (&obj);
       for (XMLElementBase::iterator c = this->begin (); c != this->end (); ++c) {
-        c->get ()->write (this, writer, objs);
+        c->get ()->pb_write (this, writer, objs);
       }
       objs.pop (self_tag);
       writer.end_seq ();
@@ -802,6 +757,80 @@ private:
   }
 };
 
+/**
+ *  @brief A XML child element 
+ *
+ *  This class is a XML structure component describing a child
+ *  element in the XML tree. There is no limit about the number of
+ *  child elements. 
+ *  This object must be provided a pointer to a factory method (in
+ *  the parent's class), a name and a list of children (which can be
+ *  empty).
+ *  Write is a class providing a Obj &operator(Parent &) operator.
+ *  It is supposed to create a new instance of Obj within Parent.
+ *  Read is a class providing a start(const Parent &) method to start 
+ *  iterating over the instances, a const Obj &operator() const for 
+ *  access and a bool at_end() method to determine if the iterator
+ *  is at the end and next() to increment the iterator.
+ */
+
+template <class Obj, class Parent, class Read, class Write>
+class TL_PUBLIC_TEMPLATE XMLElement
+  : public XMLElementImplBase<Obj, Parent, Read, Write>
+{
+public:
+  XMLElement (const Read &r, const Write &w, const std::string &name, const XMLElementList &children)
+    : XMLElementImplBase<Obj, Parent, Read, Write> (r, w, name, children)
+  {
+    // .. nothing yet ..
+  }
+
+  XMLElement (const Read &r, const Write &w, const std::string &name, const XMLElementList *children)
+    : XMLElementImplBase<Obj, Parent, Read, Write> (r, w, name, children)
+  {
+    // .. nothing yet ..
+  }
+
+  XMLElement (const XMLElement<Obj, Parent, Read, Write> &d)
+    : XMLElementImplBase<Obj, Parent, Read, Write> (d)
+  {
+    // .. nothing yet ..
+  }
+
+  virtual XMLElementBase *clone () const
+  {
+    return new XMLElement<Obj, Parent, Read, Write> (*this);
+  }
+
+  virtual void create (const XMLElementBase *, XMLReaderState &objs, const std::string & /*uri*/, const std::string & /*lname*/, const std::string & /*qname*/) const
+  {
+    XMLObjTag<Obj> tag;
+    objs.push (tag);
+  }
+
+  virtual void finish (const XMLElementBase * /*parent*/, XMLReaderState &objs, const std::string & /*uri*/, const std::string & /*lname*/, const std::string & /*qname*/) const
+  {
+    XMLObjTag<Obj> tag;
+    XMLObjTag<Parent> parent_tag;
+    this->m_w (*objs.parent (parent_tag), objs);
+    objs.pop (tag);
+  }
+
+  virtual void pb_create (const XMLElementBase *, XMLReaderState &objs) const
+  {
+    XMLObjTag<Obj> tag;
+    objs.push (tag);
+  }
+
+  virtual void pb_finish (const XMLElementBase * /*parent*/, XMLReaderState &objs) const
+  {
+    XMLObjTag<Obj> tag;
+    XMLObjTag<Parent> parent_tag;
+    this->m_w (*objs.parent (parent_tag), objs);
+    objs.pop (tag);
+  }
+};
+
 /**
  *  @brief A XML child element with is instantiated with a parent reference
  *
@@ -811,23 +840,23 @@ private:
 
 template <class Obj, class Parent, class Read, class Write>
 class TL_PUBLIC_TEMPLATE XMLElementWithParentRef
-  : public XMLElement<Obj, Parent, Read, Write>
+  : public XMLElementImplBase<Obj, Parent, Read, Write>
 {
 public:
   XMLElementWithParentRef (const Read &r, const Write &w, const std::string &name, const XMLElementList &children)
-    : XMLElement<Obj, Parent, Read, Write> (r, w, name, children)
+    : XMLElementImplBase<Obj, Parent, Read, Write> (r, w, name, children)
   {
     // .. nothing yet ..
   }
 
   XMLElementWithParentRef (const Read &r, const Write &w, const std::string &name, const XMLElementList *children)
-    : XMLElement<Obj, Parent, Read, Write> (r, w, name, children)
+    : XMLElementImplBase<Obj, Parent, Read, Write> (r, w, name, children)
   {
     // .. nothing yet ..
   }
 
   XMLElementWithParentRef (const XMLElementWithParentRef<Obj, Parent, Read, Write> &d)
-    : XMLElement<Obj, Parent, Read, Write> (d)
+    : XMLElementImplBase<Obj, Parent, Read, Write> (d)
   {
     // .. nothing yet ..
   }
@@ -848,7 +877,7 @@ public:
   {
     XMLObjTag<Obj> tag;
     XMLObjTag<Parent> parent_tag;
-    m_w (*objs.parent (parent_tag), objs);
+    this->m_w (*objs.parent (parent_tag), objs);
     objs.pop (tag);
   }
 
@@ -863,7 +892,7 @@ public:
   {
     XMLObjTag<Obj> tag;
     XMLObjTag<Parent> parent_tag;
-    m_w (*objs.parent (parent_tag), objs);
+    this->m_w (*objs.parent (parent_tag), objs);
     objs.pop (tag);
   }
 };
@@ -1297,6 +1326,11 @@ public:
     return false;
   }
 
+  virtual void pb_create (const XMLElementBase *, XMLReaderState &) const { }
+  virtual void pb_parse (PBParser *, tl::ProtocolBufferReaderBase &) const { }
+  virtual void pb_finish (const XMLElementBase *, XMLReaderState &) const { }
+  virtual std::string create_def_entry (std::map<size_t, std::pair<const XMLElementBase *, std::string> > &) const { return std::string (); }
+
 private:
   Write m_w;
   Converter m_c;
@@ -1583,7 +1617,7 @@ template <class Value, class Parent>
 struct XMLMemberDummyReadAdaptor
 {
   typedef pass_by_ref_tag tag;
-  typedef pb_zero_cardinality_tag cardinality;
+  typedef zero_cardinality_tag cardinality;
 
   XMLMemberDummyReadAdaptor ()
   {
@@ -1615,7 +1649,7 @@ template <class Value, class Parent>
 struct XMLMemberReadAdaptor
 {
   typedef pass_by_ref_tag tag;
-  typedef pb_single_cardinality_tag cardinality;
+  typedef single_cardinality_tag cardinality;
 
   XMLMemberReadAdaptor (Value Parent::*member)
     : mp_member (member), mp_owner (0), m_done (false)
@@ -1654,7 +1688,7 @@ template <class Value, class Parent>
 struct XMLMemberAccRefReadAdaptor
 {
   typedef pass_by_ref_tag tag;
-  typedef pb_single_cardinality_tag cardinality;
+  typedef single_cardinality_tag cardinality;
 
   XMLMemberAccRefReadAdaptor (const Value &(Parent::*member) () const)
     : mp_member (member), mp_owner (0), m_done (false)
@@ -1693,7 +1727,7 @@ template <class Value, class Parent>
 struct XMLMemberAccReadAdaptor
 {
   typedef pass_by_value_tag tag;
-  typedef pb_single_cardinality_tag cardinality;
+  typedef single_cardinality_tag cardinality;
 
   XMLMemberAccReadAdaptor (Value (Parent::*member) () const)
     : mp_member (member), mp_owner (0), m_done (false)
@@ -1732,7 +1766,7 @@ template <class Value, class Iter, class Parent>
 struct XMLMemberIterReadAdaptor
 {
   typedef pass_by_ref_tag tag;
-  typedef pb_many_cardinality_tag cardinality;
+  typedef many_cardinality_tag cardinality;
 
   XMLMemberIterReadAdaptor (Iter (Parent::*begin) () const, Iter (Parent::*end) () const)
     : mp_begin (begin), mp_end (end)
@@ -2115,6 +2149,26 @@ struct XMLStdConverter
   }
 };
 
+/**
+ *  @brief A helper class to convert a string converter to a XML converter
+ */
+template <class StringConverter>
+struct XMLStringBasedConverter
+  : public StringConverter
+{
+  typedef std::string pb_type;
+
+  pb_type pb_encode (const typename StringConverter::value_type &v) const
+  {
+    return StringConverter::to_string (v);
+  }
+
+  void pb_decode (const pb_type &s, typename StringConverter::value_type &v) const
+  {
+    StringConverter::from_string (s, v);
+  }
+};
+
 /**
  *  @brief Utility: create a XMLMember object without read & write capability
  */