time for an update on the development.

finally got the conversion as a seamless workflow with no change to how you are currently working:
heres an image showing what i mean:

Once the mesh has been changed, change the material file to match and they can be edited directly in the material editor

The tangents are automatically generated on import.
Currently meshes are 90% to 100% working every time, whereas still not having much success with characters and multiple anims, but still working on it.
till next update
