I believe that DISH sales rep is right. I first tried connecting through the distribution center, but got nothing but noise out of the receiver. I got it to work by going directly from dish to receiver.
So here's what I did: (1): Connect cable from dish to satellite input on the outside of RV. (2) On the distribution box, find cable from satellite input. (3) Unplug that cable from distribution box. Using
short piece of extension coax cable, run the cable that you found in 2 to the DISH receiver.
(4) On distribution box, find cable to TV. Unplug that cable. (5) Connect cable 4 to TV. (May be necessary to use another extension coax.)
Now that TV is disconnected from distribution box, I have to run other devices (blue ray, VHS) directly to one of the TV inputs. A little inconvenient maybe, but not big deal to me.