The USB adapter on the headset does not create surround sound (this is a common misconception). What the USB card does is take a surround sound signal created by the audio source and decodes it to reproduce a virtual surround sound in the headset.
For example if you're playing a game and it has a surround sound soundtrack the headset can take that signal in and decode it to work properly with the headset. NOTE: The option to select the surround sound is only available if the game supports surround sound. If the game does not have a surround sound then the surround sound option is not able to be selected.
NOTE: Selecting the headset as the playback device is done within the computer settings and selecting the sound format would be done in the game itself.