Recently pulled this out of the collection of stored disks but was struggling to get the case to open. The Internet Archive has a manual for a Cooler Master X Craft 350 Lite which while not the exact model (mine has USB and FireWire. The opening instructions are on page 1-05 (for English) and this mothod did not work. The top aluminium extrusion would not budge towards the rear of the device.
After a few goes, putting it down to return to a few times and re-reading the manual the clue was in the re-assembly instructions on page 1-07, we actually need to move the just the rear panel with the ports outward from the rear of the device. It also helps to be pushing down slightly on the top of the extrusion as the disk is spring mounted pushing upwards on to that extrusion. Once the rear panel moves out a bit the extrusion will start to rise a little on the springs. To remove it entirely you may need to peel it off the top of the disk because it is fitted with thermal pad which on mine is a bit tacky and stuck to the disk. This would be why the whole thing would not move backwards, because we were also trying to move the disk which has the sprung pins from the chassis in it's four bottom mounting points and is therefore secure from fore-aft movement.