From the post @ Creative Sound Blaster Live! Series This applies to all Live! Products, including OEM Dell, Gateway, HP, etc.
Editions, 24-bit, 5.1, and the rest. Vista 5308 may or may not find drivers on Windows Update, but even if it does, they will not support Digital Audio. Grab the ngoHQ modded drivers from 2. Run the installer in XP compatibility mode. Restart your computer.
In the audio properties in the Control Panel, to enable digital audio go to the Other tab and check digital output. Play with the Format tab to get the audio quality to your liking. You may need to restart to ensure that digital audio works after changing that option. I'm not 100% sure if creative is going to be upset that I posted this, but since they have no plans to support the card in Vista, I can't see a big problem with it.