What about FSDT Jetways. Does it control them?
There's no such thing as "FSDT jetways". They are still default jetways, just with a different visual model, but they are still controlled by the default FSX system. Which means, GSX doesn't have anything to do with them, and doesn't control anything in relationship how they operate.
When you configure a door in the GSX airplane configuration utility, it's only used by GSX vehicles.
Jetways using the default FSX animation system, are only controlled by the coordinates in the [Exits] section of the airplane.cfg