Again this is just incredibly cool what you have built Nikolay!
I think you and David Parker are part of a small group that is really helping Visio to progress and to show what is possible with Visio desktop!
I am waiting for TwinBASIC to stabilize and will release a surprise COM add-in (with ribbon) of my own. TwinBASIC add-ins because the work directly with COM are just superfast as far as I can see during testing.
No .NET interop and TwinBASIC is providing more and more detailed COM access as it develops.