No idea, but I have tons of cable ties that might do the job if I decide on another cooling method, but it's fairly easy to reseat, done it before on the P4C800-E board that I got for the Prescott. But it does sit evenly on the NB, and stays very cool even with the crappy thermal pads that are used.
The Scythe Infinity cooler sits from about 1/3rds across the NB, near the upper edge of the board, covering the "Asus P5B-E Plus" markings and right over the mosfets on the back of the board. I have the vantec steath almost sitting on the first RAM module. It seems to work well, the top of the Scythe is cool to the touch anyway.