A separate antenna of some sort is the best option for Sky receivers as they can get temperamental if you keep moving the dish about.
If you are willing to put up with the consequences, then just get another quad for the motorised dish and feed the 4th output to the TM through the motor.
What I would do is put the motorised dish alongside the minidish, and then once it is up, tell her if she wants to keep Sky, the minidish has to to stay as well. But that's me I'm a rebel.
