We're using Ubuntu 12.04.1 with Xfce 4.8. We have a script which sets environment variables needed by our software. In the past, I figured out how to run this script in the Xfce start up so that these environment variables are set up and available to gui based programs launched via icons. Recently an OS upgrade wiped out this setting and I can't remember or find how to do this. I've tried sourcing the script from ~/.profile, ~/.xinitrc, and ~/.config/xfce4/xinitrc, but no luck.
per this https://wiki.archlinux.org/index.php/Xfce#Session you should "Copy the file /etc/xdg/xfce4/xinitrc to ~/.config/xfce4/". I edited etc/xdg/xfce4/xinitrc directly and the var was in the user session.