Does anybody use and FD to EOS adapter?

Hi, I just recently got a Canon 60D, decided to get a FD 20mm/2.8 and purchased and FD-EOS adapter with it. It works well but there does not seem to be a way to lock the lens onto the adapter? When I adjust aperture and focus on the lens, it loosens the lens giving me serious worries about dropping it while shooting on a steadicam. I'm not sure if this is the exact adapter but it looks a lot like this
I have tried to mess around with the "lock/open" mechanism but it does not seem to do anything. Anybody have any experience with this?
Thanks in advance