Your problem doesn't have anything to do with GSX. Your screenshot shows you are still using the default jetways the came with the scenery, and they are NOT controlled by GSX.
As explained on the manual, default jetways in 3rd party sceneries are not replaced by GSX automatically. You must decide which one to exclude, and replace them with a GSX SODE-based jetways, which will work better, look better, and will be used by passengers.
There's a link on this very section to a video tutorial which explains how to replace a jetway on a 3rd party scenery that didn't use SODE.
