Update to Export2Maya: ver 1.1.0
Now compatible with Unity 5, support for rendering lightmaps in Vray in Maya, terrains, plus huge speed improvements to the exporter.
Export2Maya –¬†Unity Asset Store
Export2Maya – Forum

The following images are the Angry Bots example project, exported to Maya and lightmaps generated in VRay then brought back into Unity:export2maya-lightmaps-vray_07
export2maya-lightmaps-vray_05
export2maya-lightmaps-vray_04
export2maya-lightmaps-vray_03