If I understand correctly, you'll need to use a combination of manually loading the assemblies (the .NET .dlls) and then use reflection to figure out what's in those assemblies.
You can load assemblies at run time. This (most excellent) article discusses building a plug-in architecture, but you're doing the same thing - late binding to a managed object.
http://msdn.microsoft.com/msdnmag/issues/03/10/Plug-Ins/HTH,
Mike