Thermaltake Blue Orb II AM3 Install Help

My Thermaltake Blue Orb II is coming via UPS sometime within the next two days. If anybody has this cooler, do you know whether or not you have to put a new backplate on the motherboard because I originally thought I had to but according to the instructions for AM2 they don't show any removal of a backplate. And the backplate is for K8. Does it matter?

My motherboard is an Asus M4A785G-M Evo. It has a metal backplate preinstalled.

Manual is Located at:

http://www.thermaltakeusa.com/Product.aspx?C=1148&ID=15...

Thanks for the help.