i send you a pm kus. But I will post the info here too so all people can handle the button:
I made a small change to the button so you can be able to open it more easily without scratching it. Button now has a popygonal nut as a head and a polygonal nut as a base. You keep the polygonal base with pliers and you unscrew the head by using a tool for polygonal nuts. The size of the polygonal head is 10mm.