FFB trim doesn't work correctly

[Pegas44 (Andrey)]

currently elevator & aileron trim with FFB enabled works the same as without FFB enabled,
when FFB is enabled the trim should move zero-force center, without applying any shift to axis center,
so that if a player holds stick in one position, the trim should alter only the forces on stick without any effect on control surfaces.
(control surfaces don't move, only trim tabs - all other ED WWII planes behave exactly like this with FFB enabled)