I just looked at it and it is a 2850 but youre right its not 5450s im not sure exactly what cpu is has but the ID is f43 and for what i paid im not gonna bring it back.
I set the usb up like ive setup every other i just copy the install files from the ISO on the drive.
i just chose to do 2008r2 cause its known supported and ive read of people getting 2012 to work but they didnt say how.
I also have two of the drives in a raid 0