I bought a Corsair 600T, same deal with the pass-throughs. I got the USB 3 20pin Mobo to (2) USB3 splitter. ran it behind motherboard and hooked the 2 USB plugs to USB3 front panel connector and a USB(2) 320GB HDD (WD passbook I think) to the other and mounted it behind MB as a Windows image backup drive.
Works great and out of sight-out of mind.
Thanks for your comments, but I'm trying to find a different solution. Let me see if I understand your solution better to see if I can implement one similarly.