man, I've never seen an itx board with 8 sata 3 ports, why the heck would you even need USB 3 . I was just looking at the downloads, are you sure that the usb controllers is not part of the amd chipset driver? They don't list a separate USB drive on the site for this MB.
I'm sure customer support has been great with assisting, but any driver that works with win 7, is going to work on WHS 2011. Its the same code.
edit,
Did you see this, was listed on one of the reviews on newegg, it may have been your review.
Manufacturer Response:
Dear ASRock Customer
We sincerely apologize for any inconvenience this may have caused you.
For the USB 3.0, please download and install the AMD all in 1 driver at link " http://www.asrock.com/mb/AMD/FM2A85X-ITX/?cat=Download".
For the SATA ports, if drives are plugged to SATA3_5, SATA3_6, SATA3_7, please refer to user manual under page 47 at link http://www.asrock.com/mb/AMD/FM2A85X-ITX/?cat=Manual.
Try with another known good drive and SATA cable.
If you have any technical issues or warranty questions please contact our Tech Support at http://www.ASRock.com/support/tsd.asp. We can assist you shortly.
Thank you
ASRock SUPPORT
Tech Support Email: user@ASRockamerica.com
also, you can try installing the driver manually by going in to device manager, click on the usb 3 controller, should have the yellow x, search for driver option, and find the drive folder in the AMD download. this driver looks very similar to the one for the HP Microserver,
\Allin1_Win8-64_Win8_Win7-64_Win7_Vista64_Vista(12.8)b.zip\Allin1(12.8)\Packages\Drivers\SBDrv\SB8xx\UsbFilter\W764A