local axis of imported bones are not compatible with blender x-mirror mode

[Mirviy]

For a pair of symmetric bones in .pmx with "local axes" enabled(eg. 左腕 and 右腕 ), imported bones in blender are having same local X axes and opposite local Z axes, which is not compatible with default blender X-mirror manner, and also not compatible with imported symmetric bones with "local axes" disabled in .pmx. (symmetric bones should have same Z axes and opposite X axes).

( by word 'same' I mean a vector {x,y,z} is mirrored into {-x,y,z}, 'opposite' means {x,y,z} -> {x,-y,-z} .)

Editing one bone in X-mirror mode will instantly flip the roll (bpy.types.EditBone.roll) of another bone, causing it's highly inconvenient to edit imported models. (Also highly inconvenient to apply a imported .vmd file onto a character which is created in blender with x-mirror on)

Could you please change this (or add an option) to be compatible with default blender x-mirror manner? (Importing of .vmd files may also be changed accordingly)