You're right Andy!
Bypassing the projector leads to way superior results! (ok, I had to solder a 3.5mm to double RCA, as the other one was passed to the ceiling...)
I do get something to the surrounds now
The C/L/R speakers are also louder (leading to the surrounds being somewhat low)
The surround isn't as great as what I get from the DVD player, but at least there's audio all around.
I guess this will suffice until I decide to upgrade. Thanks a lot!
Mindbomb... yeah. kinda sucks. I tought there was a coax SPDIF input. turns out its an output. go figure.
Nevertheless, the surround I get from the XBOX is quite interesting.
If anyone is interested (likely to pop in search engines in months and might help someone else out?)
I configured the audio output as stereo speakers; but in XBMC I selected analog 5.1, connected directly from the motherboard's speaker jack to the curtis AUX input.
I seem to have good audio result too in winDVD running dolby pro logic II
But the best result are from the HDMI digital source converted to R/L input by the projector, not via HTPC