According to Alsa, your card is supported with the snd_ens1371 driver.
See this page -->http://www.alsa-project.org/main/ind...Module-ens1371
I have never used BackTrack, so I can not tell you if the driver comes with the system or not. What you can try, as root, the command 'modprobe snd_1371' ( without the quotes ), and see if the module loads. If you get no messages, the module loaded.
You can also try the command '/sbin/lsmod | grep snd_ens1371'. I would expect this to produce several lines of output if the module is loaded, and nothing if it is not loaded.
If the module is not included with your install, if backtrack has a package manager, look in there for it.
Beyond that, read the Alsa page I posted, it is possible to download the source, compile it, and install it. I have never done that, so you may want to create a new thread looking for help there.
Hope this helps.