First of all I apologize if this has already been covered by someone, but I was having issue locating information to find appropriate solution. After checking the bug trac I see similar bugs logged and closed with unable to replicate fault.
Anyway I hope this info may assist you if you have problem getting 5.1 AC3/DTS over SPDIF or Coax with CK804 sound, nforce chipset.
I updated the wiki with information which I hope will be clear enough to aid new-comers in making the move to linuxmce.
http://wiki.linuxmce.com/index.php/ASUS_A8N-SLI_Deluxe