Optical Out on DCX3200

[jprocdaddy]

I recently got a Motorola DCX3200 HD Cable Box from Time Warner for my bedroom where I have a Dell monitor (with no speakers) that supports HDMI and my computer's soundcard (Sound Blaster X-Fi Titanium). I've never used S/PDIF before but I thought it would be simple and straightforward, I've yet to get it to work at all. I have picture, but no sound. I'm using the only S/PDIF port labeled Optical Out port on the back of the DCX3200 and plugging the TOSLINK cable that I picked up at Fry's into the S/PDIF in on the back of my soundcard. I get the red light to shine through on both ends, but still no audio. I created a loopback of sorts with the TOSLINK cable on my soundcard in the in/out S/PDIF ports to actually know that I was getting some sort of signal and I am. This leads me to believe that there is some setting I am missing on my computer or on the cable box. I've contacted Time Warner and have gotten nowhere. Has anyone else experienced this? Thanks for your help!