I can't get the cover off my new Hoot gearbox, which came with a Hua Sheng 4-c kit from Simpson Motor Bikes. It looks to be the same unit as pictured in the thread by Irish John in the thread "Have I been conned...". The screws came out just fine, and the cover opens about 1/8 inch, but then seems to be attached to something inside. It will rotate maybe 15-20 degrees, but no farther. I tried prying with srewdrivers (without going too far in the force department) and prying with gentle tapping. Any ideas?