Fin Fuel Tak
The Super and RAF versions are fitted with a fuel tank in the fin for extra endurance. There does not appear to be any way of adding fuel to this tank at the moment and making use of it The various valves are in place and can be operated but are of little use with an apparently empty fuel tank. Are there any plans to include this in a future update and to also include it into the fuel and payload system in the vehicle drop down menu.
It's already there on the relevant aircraft. It is labelled as 'Centre2' in the fuel and payload section - there is no facility for altering the names of the fuel tanks in FS, you're stuck with what Microsoft came up with many years ago!