I have the Manfrotto 322RC2 tripod head and it doesn't seem to want to hold anything up. It will hold my 30D horizontal and vertical fine but once I put either my grip or a 580ex, the head won't hold it in place while shooting vertically. VERY ANNOYING! I looked up the specs and it says 11lbs, so I'm wondering if I can increase the friction/ the strength of the grip so it will hold firm.

