No 5.1 Audio (ASUS Mobo/VIA Chipset)

I am using a ASUS M4A78T-E Motherboard with a VIA VT1708S Audio chipset which I have been unable to get to work successfully with my 5.1 Surround Sound. I am using Windows 7 RC 7100 and I DO HAVE THE LATEST DRIVERS (for vista 64). I have even tried not using the latest drivers, but I end up in the same place. The standard jack for 2.0 speakers DOES WORK, it's just the surround sound jacks that do not. This audio chipset seems to only have problems with ASUS motherboards (learned this from the VIA forums), so I'm assuming it's an ASUS problem. I've done everything I know how to do, and I am getting nowhere. Any advice here would very tremendously useful.