Heh, I faced this dilema 3 years in a row. I'm a Lightwave guru at this point and much prefer working LW than any autodesk product...ever
including CAD purposes. However, after talking with the judges in person, they made it quite clear to me that 3DSMAX is the only product really allowed to be used for the Animation competition. The Inventor Visualization stuff is different; I don't think it'd be possible to determine the difference between one IGES file and another, at least not easily.
Anyway, from my experiences they want purely 3DSMAX. Its literally just a way of leveling the competitive playing field in my opinion. As much as I prefer working in LW, Modo, Maya (Alias), and Rhino; the animation competition is really defined as a "3DSMAX Animation" project.