I'm still working on the matter and I made some progress.
Things are going better after having put on '/etc/pam.d/common-session' the line:
session required pam_mkhomedir.so skel=/etc/skel/ umask=0027
Now, on the Ubuntu workstation, I can log-in using a 'user-domain' (which is not at all defined on this workstation).
I can run whatever program on my workstation storing new files.
... I'm not using the '/home/user-domain' directory defined on the PDC. Instead of that, I'm using a new '/home/user-domain' which has been automatically made on the workstation.
So, my problem still is how to use the PDC [homes] as my home directory. Therefore I would find the same data using any workstation.