Auto import materials with script and persist as external in .import file

Godot Version

4.3

Question

Hey, i have an Import script that assigns Materials automatically by Name to Materials in a Directory. It works perfectly BUT the assigned material is not saved in the .import file of the fbx. I guess Godot runs the Script after import and caches the materials it sets to the meshes but i want to set the materials in the .import file under: _subresources/materials/material-1/use_exteral/path = res:…
so that it is persisted in version-Control and godot does not need to run the script after every future import… any ideas?