GSX jetway replacement files can only be used for default airports. Meaning the bare defaults, not the handcrafted ones.
The issues with the ones belonging to the Premium/Deluxe package, is they are encrypted, so we couldn't create a jetway replacement file for those airports, not technically and not even legally, since we would have to break the encryption to read the enhanced airport and we couldn't possibly distribute a file resulted from such procedure.
This means, you must treat the premium airports exactly like any other 3rd party scenery bought on the Marketplace, and add their code to the Disabled list in the GSX Control Panel, so they'll use their original jetways.