I have a predator which has a traditional T Tail but almost bought the challenger. One thing I always wondered about was how does it go up and down and steer with the same control surfaces on the vtail? The only thing I could imagine was to go up or down it simply moves both surfaces evenly and then to turn one way or the other it moves one slightly more than the opposite side,, that sounds kind of phony but I guess it works? or is some other scheme I'm not seeing being used? I assume however it does work is how all vtail systems do it. I think the stealth fighter has elevators on it's wings though.

http://www.beechcraft.org/vtail/eckalbar/rudder.html