Hmm...yea that's what I thought. I haven't tried your unit yet, so maybe it'll work. The more I think about it though, I don't think the invisible unit will solve what I'm trying to do. It's good to know how they work though.
Basically I need a different players unit be able to allow placement of a another players unit. I thought with nation specific units, it'd work. I probably need to try that again.
Anyway, thanks for your help. It's appreciated : )