WTF?
I have reinstalled the WinUSB Driver V6.1.7600.16385 with Zdiag Version 2.1.1 Build 674!
Months before this i have installed and used WinUSB Driver from Zdiag Version 2.1.0 for my
Antminer U2 and the Rockminer RBoxes!!!
The Antminer U2 and the Rockminer are using the WinUSB Driver V6.1.7600.16385 without problems!!!
If i plug in the USB from Antminer U3 my Windows 7 64bit will install the same WinUSB Driver as for my Antminer U2 or Rockminer Rboxes.
Antminer U2 / Rockminer R-Box and Antminer U3 are using the same WinUSB Driver.
DO NOT TELL ME ANOTHER TIME I HAVE TO INSTALL WinUSB Driver!!!
The Driver is installed and working fine with my other Miners!
Cgminer 0.4.9.1 don't recognize the Antminer U3.

No need to get worked up about this, it's actually a quite common error and myself i experience several times that i need to reinstall the winusb driver with zadig for the exact same u3 on the same port as i first installed it. Just check it at least...
cgminer have had native support working from 4.8, with a few new parameters specifically for it in 4.9. That part been working fine here both with the precompiled windows bin and my own compiling on ubuntu.