I thought it worked - but of course I forgot the Oracle VM Manager on my second machine.
It still displayed the ServerPool1 that I had created previously.
In order to begin with a clean slate you might need to drop the database in the Oracle VM Server.
Login to the server as root and execute the following commands:
service stop ovs-agent
rm -rf /etc/ovs-agent/db
service start ovs-agent
Then the external disk needs to be added again:
[root@ovm utils]# ./repos.py --new /dev/sdb1
[ NEW ] 6ad759c5-d706-4b3a-9d14-bcffafc61fc3 => /dev/sdb1
[root@ovm utils]# ./repos.py --list
[ ] 6ad759c5-d706-4b3a-9d14-bcffafc61fc3 => /dev/sdb1
[root@ovm utils]# ./repos.py --root 6ad759c5-d706-4b3a-9d14-bcffafc61fc3
[ R ] 6ad759c5-d706-4b3a-9d14-bcffafc61fc3 => /dev/sdb1
The filesystems were back again and also the directories in /OVS.
Now back to importing a VM Template.