The GoPro is actually affixed to the bottom of the battery. Not pretty, but it worked.
To pretty things up I ordered the GAUI "Payload Mount Set" - a rectangular piece of carbon fiber and four aluminum mounting tubes. I put the new piece below the copter body and moved the Naza controller as well. The GoPro is now affixed to this "mount set' instead of the battery.
The battery is still affixed using Velcro, but I have relocated it tot he top of the copter.