First, it would be best if you didn't make the same question twice, on the forum and by emai, because it would force me to double my effort to track all messages.
I'll reply here with the same reply I already sent you via email, which has been sent our less then 2 hours after it was received:
I read in the GSX manual on page 21 that the other requirement is that "the airport in not one of those that already have a GSX customization made by FSDT, or one of the Trial airports." My KSFO airport is not a trial but rather a Full Version paid for airport.
The first requirement applies: Flightbeam KSFO HAS a GSX customization made by FSDT, that's why you can't customize it further.
Which means, what you are describing shouldn't happen, since GSX DOES recognize all parkings at Flightbeam KSFO that have a Jetway, that would be the whole point of having it customized.
However, I'm not sure you understand what "recognizing a jetway" means: GSX will never modify jetways in a scenery, if a scenery (like Flightbeam KSFO) has static jetways, they will continue to be static. If a scenery use animated FSX jetways, it doesn't need a special customization, because those jetways are automatically detected.
The only meaning for GSX to "recognize" a Jetway, is just to prevent it from displaying all 3 passenger stairs and to disable the passenger bus.