I used to hook a portable satellite dish to the "park cable" input on our old motorhome. In the A/V cabinet you have to be sure to hook up the coax labled "park cable" to the "dish In" connector on your satellite receiver. As long as there is no splitter in the run anywhere it should work fine.
That one input is the cable going to the booster. In order for it to work you'll have to disconnect the center cable from the booster and hook it straight to the receiver. There's a mod you can do to the booster plate to accomplish this so you don't have the booster hanging out of the wall all the time.
Thanks BAMA! That solved the issue! BTW- I bought the Automatic Portable Satellite Winegard Antenna. I really like it a lot. After implementing the fix from Bama, we were up and watching DirectTV in 5 min.