The Harmony 880 has a master volume control.
I am not sure what the problem is with Supertom's set up, but like Audiobear, I have nearly everything (11 items) all running thru the 990. Why would you not?
One of the questions during setup for the Harmony is which piece of gear do you control your volume thru.
Supertom, if the Harmony remote does not work the way you want it too, you would be best served by calling their customer service line and speaking to one of their nice support team members. They can get the remote working like it was intended.
Lonny