Perhaps start a new thread:
It does appear that it is likely to be either a re-badged Mitsubishi or made by them using the same components & firmware as the Mitsubishi so probably GX Developer will talk to it, however, you will need a 232 or USB to 422 converter the correct cable is an SC09 (assuming it has a 8 pin mini din socket) there are plenty of cloned cables out there.