The outer casing covers the internal mechanisms of the camera.
Remove the 2 screws(2.41mm long) on the side of the camera next to the LCD screen.
Remove the 2 screws(4.08mm) on the other side. One is located under the rubber USB flap.
Remove the last screw(2.59mm) located on the bottom of the camera.
Slowly pull the back cover of the camera.