You need to put the device in Port Mode, using the commands ##3424# from the touchpad. Then, connect the device to the USB port. If your computer does not recognize the device, you need to install the WModem drivers first. Search for WModemDriverInstaller.exe, I believe I got mine from here, or from xda-devleopers;
Hhere's a link I just found for you on Google. You may have to add ports manually in QPST until it recognizes your device.
Hope this helps...