Maya FBX export and bump layers

When exporting a Maya scene to FBX I found that if some materials have a bump
map but not a diffuse one, LayerElementBumpUV are generated in the file instead
of the standard LayerElementUV.

The problem is that these elements are no more "understanded" as UVs,
but certainly as custom user data layer (event if I did'nt verify this).

Is there any valid reason for that ? Any workaround to ensure UVs are properly
exported even if only a bump map is present ?