[Italian version]
An implicit features of the serialization of framework 2.0 is to have null xml elements using xml standard format, xsi:nil. This possibility is given by nullable types. Today the xml is considered the king of interoperability format between different systems. In the near future a possibile scenario could be to have a server that publish web services implemented with framework 2.0 and consumed from client using framework 1.x. Of course, this is possibile! But what happen if server use nullable types in its services? The proxy class is generated client-side without problems. The nullable types is not present in framework 1.x...