Thank You everybody for some inspiring ideas.
Finally I solved the problem rather simple, the .service did not work under any
condition.
The problem is obviously the login-counter in /dev/shm/ | /tmp/
ecryptfs-$USER-Private,
which for a proper unmount must equal the number of per-user sessions.
Therefore I just commented out the line containing
session optional pam_ecryptfs.so unwrap
from /etc/pam.d/common-session-noninteractive.
Thats it. Works with multiple sessions including gui-sessions.
I did no further testing, maybe it causes problems with autologins or remote
sessions,
but to me this is out of interest.
Michael Schorcht
