How to save Modified UV into FBX

greeting programmers~ I have a question for you~

after imported a FBX into Unity, I changed the mesh’s UV by using mesh.uv, then I notice that the UV is not saved in the FBX, I reopened the FBX in the 3DMAX, the UV is still as same as before it have been changed.

And another thing is if I change any importer settings in Unity, the mesh’s UV will reset itself.

Just want to ask is there a way to save the modified UV back into the source FBX?

Thank you very much~

well, after some research, there’s a way: make fbx sdk into a dll plugin, then use this plugin to save the fbx