Tank-Usage / -Selection

Seems like FS5.1 oly uses up the _outer_ tanks of my jets (FSFS). No fuel is
ever taken from the inner ones. This is somewhat of a problem on long distance
flights, since the engine stops running when the outer tanks run dry. And
"refuelling" in the air (i.e. editing the amount of fuel left via the menue) to
me is like cheating ...
Anyone knows a workaround? (Or a patch?) Tank-selection is no real solution,
since you cannot (or I'm ignorant of how to ;-) make the FS use _both_ inner
tanks at the same time.