I do not have the Denon you have, but I do have the Harmony remote, and I would think that you could plug in a macro that will tell the Denon to turn the output signal to the sub off. Then the sub should just turn itself off, if it is not being fed a signal, right?
But, then again, I just ordered one of those MX700s that Ray recommends because I found that my Harmony remote could not handle all of the macros that i now want to configure into my system.
Plus, the Harmony is only about 6 months old and the LCD screen is already starting to act up. So, as long as I am able to make the MX700 Sweetie-Proof, the Harmony will go up on ebay.
Axioms; For when you've just Gotta have More Cowbell!
60s 150 350 8s 2is
RX-V2500 DVD-C750 2900