Hi Umberto,
I see others experience this problem slightly differently. In my case what happens is that, after parking at the gate and activating the jetway, I then request deboarding, the rear luggage loader doesn't move straight to the rear cargo door. Instead, it takes a circular route to the rear of the aircraft and approaches it from the side opposite the cargo doors. It then moves under the aircraft, facing the wrong way, and then does a 180* spin to position itself correctly and raise the belt loader. After luggage has been unloaded, the luggage loader proceeds back under the aircraft, moves to somewhere at the rear of the aircraft and then does a circular route past the port side engine and the front of the aircraft back to its starting position, but not facing the way it was positioned in the gate setup.
If, after parking the aircraft at the gate, I first choose item 7 on the menu and then close the popup screen as soon as it has appeared, then request deboarding, the rear luggage loader will move directly to the rear cargo door without doing the circular route described above.
It seems to me that the GSX gate setup, as defined in the .ini file, doesn't automatically load when arriving at an airport. Instead, one has to open and close the ini file via item 7 on the menu to make the ini file active.