I know this may sound stupid, but I cannot for the life of me figure out how to take the rear view mirror off the mounting plate that it came with when I bought it. My old mirror has a set screw in the center of the bracket for holding it in place on the windshield, this new mirror that came out of a 4th gen camaro does not, it looks like a cover but I cannot figure out how to remove it, what's the trick? The new mirror has the map/courtesy lights built into it and since I have the headliner out for redoing I wanted to replace my really bad mirror with this one. Thanks for any help with this.