I've never used the zone 2 on my 720, except once when I briefly used it to send audio to a subwoofer.
I mentioned the green led's because mine stay off unless I turn that zone 2 dial to 'wake it up'. I think that was after I turned the zone 2 off using that little remote they give you.
You should be able to send any source connected to your 720 to your second room using that zone 2 function, regardless of what you're listening to in your main room; let me know how you go, as I'm interested myself!
I mentioned the green led's because mine stay off unless I turn that zone 2 dial to 'wake it up'. I think that was after I turned the zone 2 off using that little remote they give you.
You should be able to send any source connected to your 720 to your second room using that zone 2 function, regardless of what you're listening to in your main room; let me know how you go, as I'm interested myself!