As far as I can tell I'm getting 5.1 through my HDMI connection. I wasn't aware that I wasn't supposed to be. The people that aren't getting 5.1, are you sure your preferences are set right?
The 622 (and 722, of course) will output 5.1 via HDMI.
Of course, your receiver has to be able accept it.
When I
first hooked up a 622 to a Denon AVR-2807, the 622 would not output it, but that was later solved by a software update to the 622.
Be aware, that on the Denon (only brand receivers I have hooked up through the HDMI ports) do
not (unless this has recently changed) default to audio through HDMI.
You may need to go into the setup menu (of the Denon) and make that change,