Cannot get to export Opacity map

[tokola]

Michael,

thanks a lot for the explanation and example animation. It works perfectly! I haven't actually uploaded the file with the animation; I just reported it didn't work.

Let me ask a quick (and possible naive) question. How come I cannot change the material of the object? Neither the diffuse color or bitmap affect the objects (oil animated or disc) in the scene. Can it be related to this error I get about using MassFX plugin not supported in Max 2015, when opening the file?

Thanks again for your invaluable help!