can I plug in my virtual 7.1 surround sound headset with out the usb adapter straight into the digital audio out port (not optical audio) and still get 7.1 surround sound?
It is to connect to "Digital In" on am AV receiver, with simple coax cable. It has nothing to do with your headset.
The USB part of your headset plays the role of the soundcard, and it's software and drivers are responsible for the "virtual" and "surround" you are getting.