Wow, I am no spring chicken with modeling and such but my workflow/test was exactly what you did and I get white. I cannot for the life of me see any differences in what you did then I did.
Not that I am worried because I use substance and setup my own textures but this is odd.
You said you are using 2.72b ? Maybe there is something different with the FBX exporter they fixed… I am using straight 2.72.