Problem solved. You'll need a small sheet of plexiglass from Hobby Lobby (99 cents), a dime, an Exacto knife (or razor blade), and a dremel tool.
Simply trace a dime onto the plexiglass, then use a straight edge to help score a square that just touches the outside of your circle. Flip the plexiglass over and do the other side as well. Then use the straight edge to score the corners of your square (creating an octagon shape) and then do the other side. Carefully use your straight edge to help snap off the edges of your octagon. Next, use double sided tape to stick your dime to one side of the plexiglass. Then use a sanding bit on your dremel as slow speed and sand away the edges of the octagon until the plexiglass is flush with the dime. Remove the protective film from both sides of the plexiglass and drop in into the threaded barrel. Carefully replace the o-ring without getting any lube on the plexiglass, then screw the threaded barrel back over the camera. The whole process took about 30 minutes. Enjoy.