My hunch is that the 21.0 will not do "UHF Band A" - only "UHF Band B".  I'm not sure how that affects your situation.
 
I would suggest setting up the 722 using the old remotes to have TV1 be UHF Band B on one channel, and TV2 be UHF Band B on a different channel, and then setup the remotes to match those channels (which can be done without a Dish receiver).
				
			I would suggest setting up the 722 using the old remotes to have TV1 be UHF Band B on one channel, and TV2 be UHF Band B on a different channel, and then setup the remotes to match those channels (which can be done without a Dish receiver).