BleepingComputer.com: s/pdif output not working

I am trying to play a Blu-Ray disc using PowerDVD 7, and there is no audio output when I set it to "use spdif", which goes to my HDTV. I can set it to use the analog 5.1 speakers I have, but those aren't set up around my TV so they're not as helpful.

When I'm using Windows Media Player or VLC player to play video and DVDs, the sound works fine. When I try to use PowerDVD to play even DVDs, there is no sound output through the HDMI s/pdif connection.

I am using the onboard audio from the ASUS P6T motherboard, which outputs HDMI through my GTX 285 video card. I'm using the current Realtek HD Audio drivers.

When I test the output using windows sound mangement for the SPDIF output, there is no sound for DTS or Dolby Digital. What do I need to make these work?

Using Windows 7

Will my hardware simply not output digital audio, or is my TV not capable of receiving digital audio?