As you have so astutely observed, you cannot import materials into Revit with your SketchUp model not can you import MAX materials or the MAX model back into Revit. Only way is to re-assign the material in Revit. Even exporting the SketchUp model to AutoCAD and then importing the AutoCAD model will not maintain or retain your material assignements, nor transfer them to you Revit model.
Wish List item, go to AUGI for the wish list.
Mel Persin, AIA
AEC Technology Consultant
Technology to Visualize and Realize Solutions
Modeling for the Future/Drafting in the Present/Building on the Past
Mel Persin, aia