Veleno, thanks for the response!
Although you did clear some things I still can't make Vizard recognize any other texture besides the one assigned in the diffuse port of the material (unit #0). I assigned the same material under Opacity for the second object of my multi-object material, but Vizard still returns viz.VizTexture(-1) when I try to get the texture in unit #1.
The reason I am insisting in making the animation in Vizard is that I want to have control over starting/stopping the animation and I don't know of any way to do this if using 3DMax texture animations. Plus, I have the impression that Vizard (or the OSG format) creates a mesh for every frame of an animation, which makes models really heavy (I don't know if this is the case for texture animations).
Overall, which one do you feel would be the best (more efficient) approach to simulating (and controlling) a turning belt? I also attach the .max file in case you feel like playing with it.
Thanks for your help,
--tokola