
     You  should  try  having  a  .xsession  script in $HOME to do these
things.  xdm will  start  up  your  process  using  the  system  version
(usually /usr/lib/X11/xdm/Xsession), which should check whether you have
your won and change to that if you do.  (Take a copy of the  system  one
and edit it). 

     Note, that this file requires "x" access to be set.