Ok figured it out. I almost want to say "as usual", but the problem was Microsoft. You need to have a dll registred called: "extensibility.dll" which is included in VS.NET, but not in the .NET framework. It's located at "<path>\Microsoft Visual Studio .NET 2003\Common7\IDE\PublicAssemblies". Register that first and after that your .NET dll and you're set to go.
Last edited by J2k5; 22/08/04 10:59 PM.