Okay... I've had this sound chipset before...
I know that the SiS 7018 is supported using the trident module.
I, too, have an ECS board in one of my machines with the SiS 7012 chip as well. I use the i810_audio module to make it work.
I might have these backwords; so if one doesn't work, then try using the other...
just run modprobe modulename with the appropriate module name. If you get error messages, you know it's the wrong one!