On my Selectro hubs, the knob has a total of 6 screws. Three of the screws are phillips and when I removed these, the knob would not come off. The other three screws appear to be a star screw (6 points) with a fixed pin in the middle. First time I ever saw something like this. What are they called" and where can I find a driver for them. I tried to get a pic of them but I couldn't get a clear picture of them. I am assuming that these 3 "other" screws are what is holding the knob on. Both sides are set up the same way.