I just checked, and my version has GSX jetways with gate numbers (P3D4.5, GSXV2, FlyTampa KMDW). When I go to adjust airport positions in GSX, I find that there is a jetway at all A, B, and C gates.
Now, I cant recall where I got the GSX .ini file, but I'm attaching it here if you want to try it. It's not from Cartayna, so I may have gotten it via the exchange here or from inibuilds. Or I just did it myself by selecting all the gates and adding a jetway to each gate.
Bottom line is that GSX can't create ramp markings or gate markings unless you insert a jetway. Then you can have the option to add a jetway label, and select the ramp markings that outline the "danger" area for the jetway.