Pop little metal stopper of the button panel away from plastic body of the camera. (Look at pictures 1 and 2 to find a difference)

Slide the whole button assembly up until you can separate it from the body.

Gently pry green flex circuit assembly from the middle body. See picture #2.

Now you can remove button panel flex circuit from middle body flex circuit. (Read: blue flex from green flex). And separate button panel completely from the camera!