Using Notepad, open the aircraft.cfg in the aircraft's folder and find the line that says
static_cg_height = some value
Whatever some value is, reduce it by 2 and save the file. Delete the file in the aircraft's folder with the .bdp extension (CFS3 will make a new one by itself). Then fire up the sim: the aircraft will load 2 feet lower than before. Adjust to taste!
Hope this helps.