Surround Sound won't work on Xbian on PI

[mk01]

two things I check first always

1) more audio tracks - first stereo - second 5.1 - xbmc should switch to 5.1 automatically, but you never knows
2) the 5.1 audio is AAC. RPI has no online transcoding from AAC to AC3(as all other platforms of XBMC including AppleTV). so it's 5.1, but RPI is down mixing to stereo.

(there is almost none HW supporting AAC passthrough - that's why support is rare - I have not seen).