Forget FSEdit!

Any modification you need to do to FS aircraft can be accomplished using two programs.
Notepad - for anything with the suffix *.cfg
AirEd - for editing airfiles
I say don't use FSEdit simply because it was a shoddy program in 2k2, and I haven't even tried it in 2k4. Most people can do the stuff that needs to be done (adding repaints, etc) simply by using Notepad. And when you get into the real nuts and bolts of aircraft editing, you can get AirEd (freeware found on most FS sites) to edit the airfiles.