While installation I encountered a bug with the http://software.virtualmin.com/gpl/scripts/install.sh with "-host" option as in the following:
sh install.sh -host example.com
I looked into the script and there is a small miss match with the hostname options as follows:
Line# 65: Help text.
echo " --hostname|-host: Set fully qualified hostname"
Line# 75: The option.
There is an extra "-" on line# 75.
Please refer to the attached screenshot for reference.
Also, I can help with the patch file if you want me to do it.
Great script guys!