I have run itno this problem at homes with additions outside the original masonry and mobile homes with additions outside the original siding. Had to remote the antenna.
This past sunday, I had a 625 with TV1 running 4 TV's. TV 2 was outside the original masonry of the structure and the remote would not work past the threshold. I installed a 4 way splitter behind the receiver, with jumpers to TV1 out and the UHFAnt jack, and another splitter behind the 4th TV which was in the room adjacent to the addition. Got enough range on the remote for it to work from the customer's bed, though it wouldn't work from directly in front of her TV. Left her an extension and directions on how to move that antenna into her room if she felt it necessary.
I wonder if you can run a similar setup with the ant signal running throug the diplexers? I would have tried it at this customer's house, but TV2 was no joy to work on.
Myself, I have run accross several 322's that WOULD not work with the UHF remote. They wouldn't even readdress. One even had a TV1 remote that wouldn't readdress. Now, that is aggravating (not to mention, its sort of embarrassing).
Edit:
What do you know. Had one that wouldn't work today AND another one that I had to remote the UHF ant. on. So, I tried the UHF ran through the diplexers, and it worked. Now I gotta stock up on splitters because I am fresh out.