First of all, you can run evolution under KDE, so long as it's installed. You can install it with YaST.
It looks like evolution uses a simple mbox format, so you can just set up a new local mail host, and point it at the mbox file(s) for Evolution. That's one way, but you will lose any foldering information you have. See http://www.ale.org/archive/ale/ale-2.../msg00881.html