Comment 3 for bug 365779

Just discovered on http://www.adamish.com/blog/ that this is normal behavior as the bluez package has been deeply updated. On the same page I've found some good starts on how to reconfigure my system.

Basically I had to restore the original file "bluetooth" under /etc/default/

After that I've deleted my phone, repaired it with my PC and launched the command:
/usr/bin/dund --listen --persist --msdun call dun --nodetach