You don't... not quite. You configure you wireless adapter to work on the host computer. Then, in VMware running Backtrack, you use the eth0 adapter - which is a virtual adapter.
Try this as root:
/etc/init.d/networking restart (networking may be network - I don't remember).
After that, try this:
As far as your host machine knows, it doesn't have a wireless adapter. VMware's virtual infrastructure (vmnet0, vmnet1, vmnet8, host only, or bridged) always indicates a wired connection - even for me when using wlan0 on the host.