Running xscreensaver from kdm

This is definitely a newbie question...I've been fooling with linux for
about a year and gentoo for a couple of months. I'm trying to make
gentoo my 'base' distribution as opposed to 'experimental' migrating
over from RH 7.3

Anyway I like to run xscreensaver as I load my display manager (kdm
preferred). In Red Hat I added some lines to the /etc/X11/xdm/Xsetup
file. In gentoo I went to /etc/X11/xdm/Xsetup_0 and added the script but
it does nothing.

I've been through /etc/rc.conf, /etc/X11/Sessions/, /etc/X11/xinitrc and
don't really understand where I should intervene. In particular the
rc.conf file tells gentoo that I want to use kdm but I can't figure
where kdm is configured.

Could someone describe the sequence of programs run as kdm starts up?

TIA.

Terry Smith
Cape Cod USA