Greetings. There are some great instructions on how to turn on VNC access for VMs at:
https://www.trouter.co.uk/wp/?p=933
Those instructions work fine for 5.1... until the hypervisor is rebooted. At that point, the new file that was added has disappeared, and so the rule disappears.
How does one add firewall rules in 5.1 and make them permanent?