Which 777 model, exactly ?
If it's the 300 version. that's normal, because the only CS 777 supported internally is the 200, which was the only one that was available when GSX was released. Assuming the custom variables Captain Sim used are not changed from the 200 to the 300, you can probably fix this the following way:
- Open the 200 version and select the GSX Airplane customization feature.
- Go into the 3d editor and change something, it would be enough to move a door even 1 cm
- Exit from the editor, and from FSX
- Go into your %APPDATA%\Virtuali\Airplane\CS_B777-200 folder that has been created, and it should contain a GSX.CFG file. Save this file somewhere else, like your Desktop folder
- Go back into FSX and open the 300 version, and select the GSX Airplane customization feature.
- Same as before, go into the 3d editor and change something.
- Exit from FSX, and go into the %APPDATA%\Virtuali\Airplane\CS_B777-300 folder, which should contain a GSX.CFG file too.
- OVERWRITE this GSX.CFG with the one you saved before from the 200 version
- Go back into FSX, now the 300 should work with the custom doors commands, but the doors are probably off, because they are still positioned for the 200, but this would be fairly easy to fix with the 3d editor.
- After fixing all doors, you should have the airplane properly configured but, if there are several aircraft folders for the 300 (they did it for the 200) in the Simobjects\Airplanes folder, you should make a copy if your new GSX.CFG (the final version after fixing the doors) in each of these folders too.
- Once everything is working, you might want to share the file here