you probably could.
the way I did it was by drawing on the car in SU then assigning random colours and renaming them to what the colour represents.
this approach makes it easier once exported to Kerkythea as you can tell which colour needs materials applying.
if you didnt know already, double clicking on a colour on the left hand list in Kerkythea will highlight that part of the model.
first thing to do is grab all the materials available -
http://www.kerkythea.net/forum/viewtopi ... =19&t=6425
render preset 3 to test everything is set up and then 17 or 19 for your final render.