Hi,
There exists the possibility in Chessbase to add a "Null Move" (CTRL-ALT-0 or "Insert", "Null Move"). This is useful in two ways:
1. the variations are more visible: instead of having parentheses, you have a structure with a,b,c etc. variation ; and you don't have to choose a main line.
2. you can make a threat more visible (e.g. here is what happens if Blacks does nothing about the threat, you make a null move for Back, and then you play the move for White)
Anyway, it seems to me that the null move is not implemented in CTP and I just wanted to let you know. I don't know at all if it is possible to integrate it, but if not, it might be worth mentioning (or display a message e.g. there is a null move in this game, try to correct that).
chessfarrell