Thanks for posting rather than PMing me. Wanted to make sure I get as many T3 users backing me to get the problem fixed.
So far to correct the problem on the latest version of SD you have to basically perform these steps everytime before you start SD and after resuming from hibernate/standby to make sure it works everytime. I know its annoying, but atleast you can get all channels working until SD dev can get it figured out or give us an alternative.
1. Exit Streetdeck if open.
2. Open the Vinyl Deck(Via Audio Deck) that installed with the audio drivers from streetdeck dvd.
3. Under Effect in Vinyl Deck check box for "Enable Stereo Sound Expander".
4. Configure Speaker in Vinyl Deck for 6 channels. I usually click each speaker to verify sound is coming from each channel.
5. Re-open Streetdeck.
I get sound from all channels when I do this, but I have mixed results with the SD mixer. Sometimes the balance gets thrown to one side or the other. The Fader sometimes throws full volume level to the front channel.
Let me know how this works and give details on any of your results. The more information the better.
I am thinking of even trying to code my own windows volume control overlay, but I need to find out how to tell SD to treat the builtin sound card like an external one and not use their code to control it.
My last resort is to by an external sound card...crazy to have to do that though!