It seems that no one is answering. Sorry for that.
I don't use FSX so I'm not familiar with what it does.
I know in FS9 that moving jetways are part of the scenery. Some static jetways are part of the model.
Is this feature a part of FSX where it works with every aircraft?
This feature is part of the aircraft itself if Im not mistaken. You'd need to take a look in the aircraft.cfg of a default FSX airliner like the 737-800 and see how the jetway coordinates are set up. Then, you'd need to set up the 777 in the same manner. I dont know of any coordinates, but just keep adjusting the numbers till you get it. In fact, I think I will give this a go myself, and I will post up my findings when I get it.
**EDIT**
Ok, I got it to work. Looks and works great! Keep an eye out in the FSX section, I will post directions and pictures there.
My specs... A hard drive, motherboard, graphics card, some memory, a keyboard, mouse, and monitor - in other words, nothing special.
My Posky