Did what I had to do and took a chance. But was it the right way? And there are still some unanswered questions:
1. To upgrade/update Ubuntu Server 10.04 I did this:
and kept the default settings in my.conf, saslauthd, rkhunter, pop3d.conf, mysql.conf, imapd.cnf
2. To update ISPConfig i did this: ispconfig_update.sh and selected [stable] - No updates were available so it must have been the newest one
The ControlPanel still works but since I haven't started on the setup in the ControlPanel yet, no one knows if its still ok.
3. "Automated Update" in Ubuntu Server 10.04 - is this a CRON job or where do you change to "Manual Update"
4. CRON? Is it possible to update both ISPConfig3 and Ubuntu Server 10.04 with scripts as a CRON-job?
5. Sorry, but can't see difference between "update" and "upgrade !?! Please help specify it