Methods of nested classes cannot be executed. This appears to be due to .NET's naming scheme of "Assembly.Class+NestedClass", specifically the plus sign. Using something like "$" in place of "+" for bidirectional name translation would work well, I believe, since JS is fine with dollar signs in names while .NET isn't. A quick and dirty change in NativeConstructor.cs line 50 to:

Name = type.FullName.Replace('+', '$');

allows methods residing in nested classes to be called, although obviously this isn't a good fix by any means.