Just posted an update, not that much has changed this time, but more is on it's way.
The action messages and nudges are a bit more complicated than I thought at first. The problem is that xniff doesn't "know" which window is receiving the action message/nudge. I could fix it the dirty (and possibly easiest) way by just assuming that all the convo's containing a contact with the specified email receive the message. But first I want to take a look at the negative side-effects of that method and compare it to other ways of working around this problem.
Suggestions are welcome, ofcourse