USB Fan won't shutdown

I have an HTPC in an entertainment center cabinet and needed a fan to blow the hot air out the back through one of the holes you're supposed to run wires through. I got the Thermaltake Mobile Fan II External USB Cooling Fan, and bolted it to the hole. It works really well and moves a lot of air. Only problem is that when I put the computer to sleep or shut it down all the way, the fan stays on. It only stops if I turn the PSU off. I can't tell which device it is in the device manager (or if it is there). I could probably turn off all the usb ports in S3 through the bios, but I need the USB IR receiver active so I can bring the computer out of sleep with the remote. Anyone have any ideas how I can get the thing to turn off in sleep state? Don't have the specs on me, but its a Foxconn 965 micro atx mobo, q6600, and an ati 4370. The one bad thing about the fan is that it has speed control, but no off switch.

Well, that's not exactly the answer I was hoping for. Since the fan is external to the case, I'd rather not run a regular case fan out of it that I would have to carefully detach every time I want to pull the pc out. Adding an on/off switch is not a bad idea, but I'm trying to set this rig up so that one button on the remote turns everything on and off (it kind of defeats the purpose if I put it to sleep with the remote and then have to walk over and reach into the back of the cabinet to turn the fan off). I thought there was a way to disable power to USB ports in the device manager? I suppose telling it not allow a device to wake from sleep and telling it to not provide 5v power is not the same thing.
Thanks for the response!