What must I edit and where in the cfg file should I look to get the jetways to dock to lets say a posky 737 originally made for fs9?
You can edit the aircraft.cfg file to make any aircraft dock with the default jetway. Mdaskalos had explined it in the following quote.
Quote from mdaskalos
exit.0 = 0.25, 67.5, -8.75, 8.25, 0
I've shot from the hip a bit there, because I'm not at my FSX computer, but those numbers will get you in the ball park. The three numbers in the center are the main one: "67.5" is the "X coordinate" the distance (in feet, apparently) the main exit is forward of a point (perhaps the rear wheels). A bigger number makes the jetway attach further forward on the plane. "-8.75" is the "Y coordinate", the distance left or right of the plane's centerline (negative apparently being left). The jetway WILL go into your plane or stop wide of it depending on this number. "8.25" Is the "Z coordinate", the height above ground the jetway attaches.
I did some playing with the final number at the end, hoping it adjusted the angle at which the jetway attaches (because the body has started its taper to the nose at the main exit of a B777), but I couldn't get it to do anything positive.
I suppose by tinkering with the numbers, you could make the jetway attach to any point on the plane you want. Just park it within the jetway's reach.
Hope this helps