XFce 3 startup script(s)

[wolfgang]

on debian unstable, i use kdm as login manager and xfce3 as my "desktop". i 
have followed the howto
http://kmail.kde.org/kmail-pgpmime-howto.html
to set up kmail 3.3.1 with pgp/mime, but i cannot find where to put the 
command
 eval "$(gpg-agent --daemon)"
properly ... i have tried ~/.xsession ~/.xfce/xinitrc /etc/X11/xfce/xinitrc 
without success.

when i run eval "$(gpg-agent --daemon)" in an x terminal and start kmail from 
there, it works.

i know xfce3 is not bleeding edge, but i still love using it and would 
appreciate any suggestions to solve the riddle ...

best regards,
wolfgang