First of all you need to be running VSpshere ESX 4 update 1
and your VSphere Host needs to support passthrough configuration
1. You can set this feature in the BIOS if it is a newer chipset if you do not have this option then it is most likely not going to work- Look in the BIOS for something like Intel vt-d or VT IO
2. If your machine has passthrough configured in the BIOS then go to the VI Client – Select the Host, select configuration tab then select the Advanced Settings under Hardware area.
3. You will then have to select the USB and check off for passthrough for the USB device
4. Also make sure you upgrade the virtual machine hardware to version 7 and upgrade the vm tools
5. Add a USB controller to VM- the VM needs to be powered off to add this device
You should now be able to see the USB device on the VM
