Reversing a manual lens for macro

[Shakespeare]

Here's the great thread on another forum about reversing a manual lens for macro work...

http://www.texasphotoforum.com/viewtopic.php?p=30553

my question is there at the bottom, and I'll repeat it here, because I can't get a reply over there.

I'm pretty anxious to get my reversed lens working, but my lack of knowledge with FD lenses has gotten in my way. So, here's my 50mm 1.4 that I recently purchased just for reversing. The iris seems locked, so that I can't perform the above step: "On the older FL or FD canon lens you will need to put something on the backside of the lens to hold iris of the lens in the wide open stage, that way the fstop ring when turned will control the fstop. I used a small piece of a gardenhose washer"

http://img.villagephotos.com/p/2003-3/132253/IMG_8708.jpg

So how do I unlock it? And what have you guys been using to hold it on place once you get it unlocked?

Thanks!

[chtgrubbs]

Look at the aperture ring and there will probably be an "A" at one end of the f/stop scale lined up with the aperture indicator mark. The lens is locked in Auto. Push the button next to the A and you should be able to turn the aperture ring to set the desired f/stop. One of the two silver tabs which ride in the slots on the back of the mount ring controls the opening and closing during exposure. I gather the instructions call for for sliding it over and hooking it to the black square post by using a hose washer. I've never done it myself, so that sounds as good a plan as any. Good Luck!