Post render MEL restart render

#1

I am trying to render out an object in hundreds of materials.

I do this with a post render mel wich changes the material after rendering.
But then i want to restart the render again.

Is there a way to do this? The batch render command does not work.

Tnx!

#2

This is what is executed if you start a rendering from within the UI:

renderWindowRender redoPreviousRender renderView;

Maybe it works if you execute it at the end of your script.