generally most games already have built-in mechanics which make direction finding easy even on 2.0 headsets. sounds from the rear generally have a different tone and are muffled with lower volume than sounds from the front.
also, its possible to use virtual surround and convert the HXC into 5.1 headphones. razer has a free software for this, razer virtual surround (although its not the best quality compared with your other options). if your onboard soundcard has the option you could use that. last, soundcards often have it built in, the cheap xonar dg is a great option to upgrade from onboard and has it built right into it (dolby headphone).
some people love virtual surround, others do not. its purely a preference thing. keep in mind...