My MBP 13inch does not show more than a stereo out ( the 5 and 7 channel out comes up as grey - unselectable options) option. Why does this not work? Has anyone ever got more than 2 channel out from the mac? How?? Earlier this week I had problem with the sound being recieved by the amp, but that is fixed now as the optical cable was weak. Anyway. Thanks for reading.