I checked via GSX config menue: the exclude file is there, the ini file is loaded. However, for all jetways it tells me "gate has 1 bgl jetway". How can that be?
According to the screenshot you posted, that's not what GSX is telling you. It's telling you that scenery has a SODE jetway.
As explained on the manual, is the scenery (more precisely: a PARKING) already has a SODE jetway, GSX will not allow you to further customizing it, assuming if the scenery developer took the effort to include SODE jetways in the scenery, since they integrate with GSX boarding/deboarding and passengers will use them, it's no use replacing them with GSX L2 models.
I see you have a customization file made by Cartayna: maybe that file was made to customize all the various GSX parking positions for vehicles, custom pushback locations, operators, but NOT jetways ?
Or, possibly, if it was made with GSX L2 jetways, it came with instructions how to disable the SODE jetways that came with the scenery ? That answers the 2nd part of your question: why you don't seem to be able to exclude jetways with the GSX Control Panel: this is entirely NORMAL, since the GSX Control Panel can ONLY used to exclude jetways made using the default animation system, by creating an Exclude .BGL, which is the standard way of excluding things in the simulator.
SODE jetways, instead, can only be excluded by removing them from their SODE XML file, usually located under %PROGRAMDATA%\12bPilot\SODE\XML and it's something you should do it yourself, for the following reasons:
- Those files were made by the original scenery developers, and it wouldn't be right if GSX tried to modify them automatically. This is different than creating an Exclude file, in our own folder, which exclude the objects without touching any of the original scenery files.
- Those SODE XML files might be used for other SODE-related things in the scenery so, ideally, you would want to be sure you are removing *only* jetways, not just the whole file.