3dsMax Materials id to Unity, problem :(

Hi, I have a little problem, i have a model in 3dsMax who has all their Materials ID assigned, when i export this model to unity, unity automatically assigned different materials to each one of my materials id, but when i put my tiff file in my defuse channel of a transparent/cutout/vertex-lit material, unity do not recognize my alpha channel and displays my character all transparent.

Thanks for read, i hope its has a solution.

Regards

Elías Palomo Reyes