Trims on different flight mode

I’m trying to fly my turbine plane (kolibri on Twister jet) with pixhawk 3dr. latest MP / plane 3.7.1 on PC/FC.
everything works greats on ground and I can fly manual no problems. So I start the plane on manual , the particurity of turbine is to start trim throttle on zero …and then move the trim to 50% to arm the ecu…start the turbine etc… as soon as in flight at a fair speed (let’s say more then 9 m/s) I siwtch to flight mode FBWA or FBWB the turbine swicth off… I guess the throttle trims must be different in flight mode and does not keep the value of manual ? how can I keep same trims for all flight mode…to switch off the turbine there is 2 ways …either lower the throttle trim o switch of turbine with a remote switch set up control … any ideas ?