[gdm-list] Create custom session

[Marco <netuse lavabit com>]

Dear list,

I'd  like to  create a  custom session  for GDM  using the
GNOME  environment, but  I face  some problems.  What I've
done so far:

∙ I  created a  file /etc/X11/sessions/my-session.desktop.
This  session  appears in  GDM  for  all users  and  calls
gnome-session --session my-session.

∙ I created a file
$HOME/.config/gnome-session/sessions/my-session.session.

My two problems/questions:

∙  Where  do  I  have to  save  my-session.session  to  be
available for all users (in  contrast to save them in each
users  $HOME/.config/…).  The  other  sessions  reside  in
/usr/share/gnome-session/sessions, but I  don't think it's
a good idea to write  configs in /usr/share. Maybe there's
some place in /etc or /usr/local I can use.

∙  How/What  to  change  to set  this  custom  session  as
default  for  *one*  user?  I  tried  to  set  $HOME/.dmrc
”Session=my-session“ with no luck.

GNOME 3.2.1
GDM 3.0.4

Marco