Adding class types to engine's namespace

Hello,
I tried this one in the other forum, I am trying my luck here:
I was wondering if it's possible to add class types defined in a type library calling AddTypeLib() instead of adding a specific instance using AddNamedObject(). I tried to do it on IActiveScript interface to VBScript and to Python in some implementation of an embeddable scripting editor and though the return code from AddTypeLib was OK- the class types from the type library were not familiar to the engine.
Is it possible with Python? how should I address this class once it's in?

Thanks!