Stupid Q - How do you add WM's to KDM?

[csj <csj@mindgate.net>]

There it is. I have installed KDM and I don't know how to add XFCE and ICEWM 
back to the login options (I think they're called sessions). How do I add 
these window managers to KDM? What file do I need to tweak?

My previous experience with KDM was with Mandrake, which appears to handle it 
automatically. In Debian, I had been using GDM, which appears (that word 
again) to have better documentation. But I like KDM's new features, such as 
automatic login for non-root user.