Tritton AX Pro - configuring decoder with onboard sound

Hey gang,


I decided to spoil myself with a birthday present and just picked up a pair of Tritton AX Pro headphones. I got the full blown package that comes with the external Dolby digital decoder.


Everything sound great when i hook them up to the consoles, and the USB connection to my PC works great too.


However, I don't seem to be getting digital output from my onboard sound card (MSI p45 platinum) despite the fact that I went into control panel and enabled the digital output. I looked into my mobo a bit and it doesn't say anything about dolby digital, but rather that it has digital 7.1 surround.

Do i need a dolby digital soundcard to get the dolby digital working for PC games etc? I realize that sounds like a dumb question, but I thought thats what the dolby encoder does? Any insight would be appreciated.