I have an H24-100 receiver (non-DVR) hooked up to my 45xx Replay and have never had this one, or any other HD receiver I have used, shut off the analog connections when HDMI is also connected. I actually have 2 different ones (a h21 and a H24) connected to Replay's using the composite connection to connect to the Replay, but also a HDMI cable which bypasses the Replay and allows me to watch HD directly on my plasma sets if I wish.
At one time, I also had my H21-200 DVR connected to the Replay and it worked fine. However, I thought it was a waste to use one of the HD tuners in the DTV DVR to control the replay, so just got another HD receiver (H24) for the Replay, and let the DTV DVR control the two it has.
Using the Paterson Tech USB cables to control channel changes on all of them without issues.
Can't imagine his HR24 would act any differently than mine do.