Make Default- Classes Subclassable in LotusScript

We have some advanced applications, where we need the default classes NotesDocument or NotesUIDocument or any other to have some special functions like "SaveWhenModified" or "ReplaceItemValueHashed" (only mark the document as changed when the value really changes), or auditing.. It would be very convenient to write code like: 

Class NotesDocumentAdvanced As NotesDocument

But when you try you get "Cannot subclass: NOTESDOCUMENT". 

You can workaround that by manually writing all the necessary functions / subs in your class and simply calling the NotesDocument- Functions for them, but it is not convenient (and you cannot have optional parameters or overloading in functions that you define manually, but the Standard classes do)...

Please allow us to subclass the default classe in LotusScript

Torsten Link