Hi, I have a problem with my Agfa Parat-1 half frame camera. It doesn't focus correctly, and that's because the lens doesn't rotate when you turn the focusing ring. I've removed the focusingring-lens assembly from the camera. I've found out the lens and the focus ring can rotate independently of one another. Behind the part that says ''1:2.8/30 agfa apotar color", there should be 3 screws holding the whole thing together. I can see those screws from the back of the assembly. Does anyone know how i get to those screws, or how to remove that part without scratching/bending it? I can make pictures if necessary.