Good a.m. I have had the same problem....actually every time I go out on a trip and try to connect my dish.
The connection is possible; you do not need to run a separate coax.
If I were closer to my trailer, I would go and look at my diagram which I made for myself because I cannot remember how to do the deed every time.
Experiment!! The little jumper under the credenza has to be changed because I believe that the TV booster not only has to be OFF but isolated...
Bypass the booster. Good Luck