Problems adding AssemblyReferences to the SyntaxEditor

Really like the editor ... 

I tried to attach assemblies using "Add' and have problems. I would also prefer to use references already in the app domain.

The follwoing works fine:

projectAssembly.AssemblyReferences.AddAllInAppDomain();

Problem is that I don't want to expose all dlls to the user. I tried to selectively remove them, but it didn't do the trick:

foreach (var projectAssemblyAssemblyReference in projectAssembly.AssemblyReferences)
{
   if (projectAssemblyAssemblyReference.AssemblyName.Name.StartsWith("ActiproSoftware"))
   {
      projectAssembly.AssemblyReferences.Remove(projectAssemblyAssemblyReference);
   }
}

Any ideas?