Automatically starting KDE 4 on second X screen, how?
 

This should be dead easy, but I seem to be unable to find the magic google terms.

I configured a second and third X screen (no Xinerama and all that) in xorg.conf. They are working, because I can see the typical X-cursor on them and move it around. So the next step is to automatically start a KDE desktop on them at login. How do I do that?

The system is Kubuntu Intrepid Ibex with KDE 4.1.