I'm trying to remove the rotating tripod mount from my new 200mm f2 (IS) lens, as I only do hand held, and think it is possible without actually getting out a hex wrench... anyone know how? (there's nothing in the lens manual) found this past post on removing the 300mm : http://www.photo.net/canon-eos-digital-camera-forum/00OknI but none of those seems to work. The lock screw unscrews to allow rotation, with click stops every 90 degs, but does not pull out any further than that. There is no red mark on collar to align with lens red dot. I have gone around 360 degs pulling every which way but there seems to be no 'free' position. anyone shed light?