To write a new .NET server assembly
Use the .NET Wrapper to generate a C# server skeleton. See Writing a .NET Server Assembly.
Build an EntireX RPC client using any EntireX wrapper. See EntireX Wrappers. For a quick test you can:
use the IDL Tester; see EntireX IDL Tester in the EntireX Workbench documentation
generate an XML mapping file (XMM) and use the XML Tester for verification; see EntireX XML Tester in the XML/SOAP Wrapper documentation