I have purchased the trijicon night sight set from Kahr for my PM9. Apparently the new trijicon sight comes with both posts threaded and two installation screws. The rear screw is easy to install. However, I have found no way to install the front screw. Approaching from either the front or the rear of the slide the angle is wrong to get even a thin screwdriver tip into the screw head. How have others done this; I am perplexed.