Hi all, I've had my 24" iMac wall mounted for a little while and I want to go back to having the stand on. The only problem I'm seeing is.......how do I put it back on? It looks like there's a key in the center for the stand (on the arm mechanism inside the imac) but every time I try to get it to latch I hear it give before the holes are exposed (to get a screw in to hold it in place.) What am I doing wrong here? Shouldn't the mechanism inside the imac be able to be pulled out?