Using the VS2008 version I followd the hand-on-lab with an own service. Everything worked alright up to Ex #7. The created client proxy (see \WCFConverter\Tests\WCFConverter.Client\Service References) is not compilable, as it generated duplicate implementations from WCFCommonData::ParameterValue. Using svcutil to generate the proxy class works well (ConverterProxy - Kopie.cs).