After you have installed the client software on both nodes, create an Exchange policy and enter the virtual name in Clients tab.
If you also want to backup the O/S on the individual nodes, create another policy of type MS-Windows-NT and add the physical hostnames in the Clients tab. Add drive letters in Backup Selection tab or ALL_LOCAL_DRIVES. Just remember to add Exchange data folders/drive letter to Exclude List in both nodes' Host Properties.