Thank you very much for all the warm replies!

I think the heart of the problem is the design in A. (it is doing too many things...)

In fact both A and B are classes from Visual Promatrix, A is subjected to changes when the developer of VPM distributes newer version and as a user I am suppose/advised to make change at subclass level (that is the B).

Anyway, in this case, it seems I won't be able to avoid changing A's Init method (knowing its last line DoDefault actually does something), since I can't avoid changing A's code, I have decided to go ahead and change it there and of course take a serious note in my documnetation in case I need to reapply the same modification.

Again, thank you for all the guides!