I am having trouble getting all of my speakers to output sound from my Mac mini.My setup is a cable box->sat/cab input and Mac mini->DVD input. This all goes out to my tv. I have 4 speakers connected (2 front, 2 rear).The sat/cab works fine. I have the VSx43 set to stereo alc/ext. stereo. Sound from all speakers.The Mac mini only gets sound from the front speakers. When I try to change the sound setting, stereo alc isn't available, only stereo or PCM. What's up?