I feel like I'm missing something easy here. I need to remove the case back of a GW-600DA to replace the battery - the old battery in it won't take a charge any more. I've opened plenty of G-Shocks, but can't figure out how to take off the end caps to remove the case back. The only removable parts that I can find are one screw on each side and the four screws on the car back itself, but removing those doesn't seem to get me any closer. Anyone have any ideas?