In order to find the adapters code, Lightstreamer library tries to dynamically load dlls from the current directory. However, static dll references may cause cached dlls to be used (as finally suggested in this thread).

Please try renaming all the namespaces in the classes that you recompile and use the new names in the configuration files and launch script, if needed. You probably just need to run your own executable, as created by your sln, which includes your own version of StandaloneLauncher.cs, in the DotNetCustomServer.bat script.