Dish makes the rules.. The problem is this: you have to CLOSE the existing account and open a new RV account. When you CLOSE the existing account you have to return the leased receiver.
Problem 2: They may not let you use the same receiver for the RV account, you may have to "Upgrade" to a VIP-211K for the RV. (This I am 100% unsure of however).
Of course, repeated calling back sometimes helps.
Two more things that might help.
1 Mention that DirecTV can still offer Distant Network Service
2 Mention that with DirecTV, you can run multiple receivers or even a Dual-channel DVR and get all your Stanard Def programming, where as with DISH, and a DOME type antenna... (In motion dome) that is not possible.