I'm attempting to remove the rear pin in order to install a pin for the belt clip. The instructions say: 1) Make sure firearm is unloaded. 2) Remove rear frame pin - use punch and lightly tap with small hammer. The rear frame pin doesn't seem to want to come out. I've "lightly tapped" and not-so-lightly tapped it, but it won't budge. I don't want to break something...am I missing a step here?