PBS behind proxy

Can I ask where you are setting the port? We tried this, but don't seem to be able to specify a port in the Add Storage, Proxmox Backup Server. If I put a port in the Server field, like backup.example.com:443, I get an error.
 
Ah ok thank you - so this is for Remotes. I was hoping this could be done with client PVE clusters, but it seems that a port selection is not currently possible there (i.e. for backup to a PBS storage you must use port 8007).