As you might have read in the GSX manual, if a scenery already has SODE jetways, we won't touch them, This was also explained in our first GSX L2 announcement, back in June:
http://www.fsdreamteam.com/forum/index.php/topic,17940.0.htmlAlso, if your addon airport already use SODE jetways, we won't touch it, assuming a developer who made the effort to support SODE, already did jetways in the best possible way so, we won't allow customization of these sceneries.
Offering an official solution for SODE jetways, like the GSX Control Panel, which excludes jetways without touching any of the original scenery file, would have meant searching and removing files that do not belong to us!
But, if you know what you are doing, you can do it yourself so, if you remove the SODE XML file for that scenery, you'll be able to customize jetways even at those airport.
BE CAREFUL, though. Some sceneries use SODE not just for jetways, but for other objects too, like docking systems, windsocks, etc. Blankly removing these files would kill such objects too so, the proper course of action in these case would be EDITING the SODE XML file, and remove JUST the jetways.