How to create COM Servers with IID_IDTExtensibility2 interface

[Penfold]

Any win32 COM gurus here ? :-) [eg Mark Hammond ;-) ]

What I am trying to do:
    Create an in-process COM Server capable of being used by Excel as a
"COMAddin"

According to a very small demo I have downloaded from Microsofts website,
for a COM object to be used by excel as a COM Addin
it must implement the interface IID_IDTExtensibility2.  I know the GUID for
this interface and its "defined methods".

How can I do this?  All of the examples I have read in pythonwin (build 132
on python 1.5.2) imply that you can only create
objects with particular interfaces that are defined in the pythoncom module
itself eg IID_IDispatch, IID_IConnectionPoint etc

Now pythoncom.IID_IDTExtensibility2 is not a defined variable.  So is there
any way I can go about registering an object as
satisfying this specific interface??

Any help appreciated,

Des