P.S. I just found the page were I had read about jetway speed but they may have made the same mistake, trying it out would quickly show you whether it works or not.
http://www.ehow.com/how_12224699_make-downloaded-plane-use-jetway-fsx.html
I think you are right. As my information from the A321 showed, the one they say is the Jetway speed, is actually the exit door opening/closing speed.

You would edit FSX config instead of the aircraft config, to get the desired effect.
I don't think it can be changed in the FSX config file.
This is how I believe it works: When creating an animated BGL file, like the jetway, in 3DS Max, gmax or even FSDS, you need to give the movements animation info, in seconds, and what it does within those seconds. I'll create something in gmax (it will be a basic object, nothing fancy) to show what I mean.

I will also try to get the correct answer on this when I can. I need to go to the development forum and ask them. Not sure how long before I will get an answer.

Mark