Most standard name receivers that have Zone 2 or "multi-room" capability will only accept analog sources for that output. I believe that is true for the Onkyo TX-SR607 as well. At least according to this one update.
www.polkaudio.com/forums/showthread.php?...estions-about-Zone-2
I think what one918 is doing to process digital inputs is setting up multiple receivers with one per zone. So I read it as the TX-607 is the receiver he is using to drive his outdoor setup while a different receiver focuses on his indoor setup.
XBMC out-of-the-box was never designed to have dual audio output without extensive coding within the asound.conf file. What makes it harder is the coding is unique to each system configuration so you can't just copy and paste unless you have the same exact box as someone who has successfully coded their asound.conf and is sharing it.
The easiest answer seems to be from additional code that a developer in the XBMC forums wrote (XHBL is his alias) which allows one to set a second audio stream from the SYSTEMS menu. Happily, _PJ_ was able to adapt this code and compile it into his builds of OpenELEC.
openelec.tv/forum/13-miscellaneous/30068...port-xbmc-eden-patch
I am using one of his ION builds right now and it is a FABULOUS experience. In my den, I can enjoy full 5.1 digital sound from a music concert while my box is also downmixing it to 2 channel analog which is then sent to the rest of the house via my single receiver's Zone 2 and an additional 12-channel analog amp.