Simply:
If the trim axis is its own independent analog axis, then you can map it in BMS. If the trim axis actually skews the X/Y axes at the stick itself (as with older analog joysticks), then you cannot implement it in-game.
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-Home Fries
XBL: The Mad Gonzo
The average Naval Aviator, despite the sometimes swaggering exterior, is very much capable of such feelings as love, affection, intimacy, and caring.
These feelings just don't involve anyone else.