Had this problem many times before. I had lenses with Ricoh Pin that supposedly to be fitted to my Super Program only, but many times I forget this and fit them to my K20D. The pin is a brass needle, about 1mm, so it could be bend somehow using adequate force . Facing the camera from above, right hand on the grip and left hand on the lens, try turning the lens harder (to off position), with a little tilt on the left side (where the pin is). Camera mount are designed to withstand much tension, so worry little.
Good Luck!
Last edited by minahasa; 09-11-2011 at 10:46 AM.