I have GSX Level 2 at PHKO airport there are no jetways
There aren't any jetways on the real airport too.
so I must use stairs but they won't reach the door exit on my CLS. 330-200 RR.
It seems you haven't configured the airplane. Every airplane that is not already included with GSX must be configured with the included editor before it can be used with GSX. Have a look at the GSX manual, the chapter named "Airplane configuration", which starts at Page 52.
