It was the Harmony controlling the receiver. The dock is essentially a passive device and other than charging the iPod, it responds to what the receiver wants.

I did manage to get it working last night, however. In talking to a level 1 rep (the level 2 reps didn't catch it), he mentioned to get the AVR remote to go to The Bridge function in one key press (rather than two) and set it up for DMP and not TAPE. Now, I select the function IPOD, then DEVICES, find DMP in the menu and the input appears on the AVR's display as it should being THE BRIDGE. I could control the volume and the iPod menu was shown on the TV, Play and Pause, but could do little else. Likely the individual functions are not set up properly in the SETTINGS menu for our Harmony account. I'll have to make some changes to enable song selection, venue selection (artist, album, genre, etc.) and so on, but at least it's working now.

In all fairness, the Harmony remote is a good piece of equipment and is very easy to use. The downside is, it took Harmony three weeks to get this problem worked out. I was one step away from returning the remote. Hopefully, I'll be glad that I didn't.