Sigmatel audio drivers and line in issues

I have a dell xps m1530 and it uses the SigmaTel audio drivers. What I'm trying to do is pretty simple, and I've done it with a normal desktop audio card easily. I have surround sound speakers, and I use a monitor to play my Xbox 360 on. I'm trying to run the 360 audio through my sound card and use my computer speakers. I have a converter, so the xbox audio goes through a single standard computer audio jack.

So I plug that into my computer, and chose "line in" in the sigmatel selection screen, but the audio doesn't work. Is there any way I can make the xbox audio play out my speakers?

 

Have you installed KB950125 (Media Center Xbox 360 Extenders for Windows Vista)? It fixes several issues.

http://support.microsoft.com/kb/950125

 

I have a desktop PC with the Sigmatel sound solution, and for some reason the Line-In just will not map to the Line-Out. According to the sound properties the sound is *getting* to the card, the volume thing is at max and registers incoming sound, but just won't come out the speakers.

I ended up just running the device (my XM home receiver) directly to the speakers since they can accept multiple input sources. Kind of annoying tho.