So I decided to write this small C program based on gio which automatically mounts external devices. I let it autostart at login et voilà everithing works as expected.
Symply put the gio-autostart.desktop file in the /etc/xdg/autostart directory and the programm will mount external drives at log in. You could also run it manually without parameters.
UbuntuUbuntu users can also install using my public repository on launchpad