Now the bottom plastic cover can be loosened. It is secured with five screws: one above and one below the serial number; one beside the tripod mount; one on the edge of the battery case; and the last one (it can't be seen on the picture) on the right side beside the "flap" on the back of the camera.

The screws can be very tight and you must be very careful not to strip the slots in the head of the screw. I suggest that you exert very firm pressure down on the screwdriver, and only then turn the screw slowly but certainly.