Thanks for that!
Unfortunately Linuxliveusb is an Windows-Tool.
I have no Windows-Machine at home. Only Mac.
In the end Unetbootin for Mac worked fine for me!
FYI:
After setting up some Network-Parameters at the WebGUI of OMV the Ethernet-Card in /etc/network/interfaces changed back to "eth0".
Had to change again to "eth1".
Hope for the last time.
grtz