So I just picked up my new Mac Pro, and have it set up in the living room, much to my girlfriends' chagrin, while I wait for my new monitor to arrive. Anyways, I have it plugged into the TV so I thought to myself, 'why not plug it into my surround set as well?' I went ahead and plugged my stereo receiver into my Mac Pro's Optical Out port, but the Pro doesn't seem to be detecting my stereo, as I cannot select the digital audio as a device for sound output. So, in the meantime, I am stuck with 2.1 through the line out jack. Has anyone else had this problem? Any ideas?