Look at XSPC's site, there will be one.
Should be included with the kit as well.
And I would think it would be fairly simple to figure out, AMD boards have a backplate built in.
EDIT: Wonder if this has anything to do with it?
http://www.xs-pc.com/manuals/
Was fairly difficult to find, after all it was in the navigation bar on the XSPC homepage, fairly obscure place
.