I remember reading some other thread earlier where a guy said surround sound doesn't work for any headset that has to go through the adapter. not sure if it's true, just something people should probably look into before they buy.
Well that makes sense. You would need a fiber or HDMI connection to get Surround, so if the adapter requires you to filter sound through it somehow then it would only come through as stereo.
If there's a way to just use the adapter for the chat audio and still keep the headset connected to the surround source then you might be able to work around it.