Z6A Headset With Bootcamp On An iMac?

I am running Windows 7 on my mac with bootcamp for gaming. I am currently looking to buy a TurtleBeach Earforce Z6A. (http://www.turtlebeach.com/product-detail/pc-headsets/ear-force-z6a/44) I can tell that my iMac does not have the required ports for the headset to work as it needs four jacks for different surround sound capabilities so I have found a Sweex 7.1 External Sound Card (http://www.amazon.co.uk/Sweex-7-1-External-Sound-Card/dp/B00265L1S2) and I beleive it has all the ports necessary for the headset to run but I do not want to spend a lot of money on this headset and be incapable of using it so if anyone could tell me if it would be possible to use the Sweex 7.1 External Sound Card to allow me to use the Z6A with my mac I would be exteremly greatful.

I have a cheap headset but am unable to get the microphone attatched to the headset to work with my computer using the line-in jack on the computer and the Sweex Sound Card. It may just be me not installing it correctly or I don't have the required drivers or external microphones simply do not work with my bootcamped iMac.

Any help would be appreiated. Thank you! 🙂