Exporting FBX meshes in local space, not world space

When exporting to FBX from Ruby, the pivot of the meshes are always in the origin at 0,0,0 globally.
I would like to export the scene with the meshes having their pivots at their local 0,0,0.
The way I am doing it now is transforming each entity (instances more precisely), with their inversed transformation, that will move them to global 0,0,0 with the vertices ok. Then I save a separate file with the actual pos/rot/scl before they were transformed. After export, I revert back the inversed transformation to put them back as they were.
This is tedious and I dont have the actual transform in the FBX file.
Any ideas ? Should I actually move the polygons before export or what?