I am new to GSX, and have searched the forum for my problem, but have not found anything.
This has been discussed several times on the forum, for example here:
http://www.fsdreamteam.com/forum/index.php/topic,6373.msg55540.html#msg55540So, it's not a GSX problem, which simply trust the AFCAD with the data it finds, and you would have ended up in the same position if you used the default "Go To Airport" FSX menu option.
It's possible to adjust it with ADE, but it must be done by editing each scenery, and would require a different method for 3rd party sceneries, that usually don't use the AFCAD to indicate the stopping tee, but use their own custom textures.
You will surely get better results if you use an FSDT scenery, since our sceneries provides GSX with more data compared to what it's possible with the AFCAD, and it also works by recognizing the airplane type used.