Hi,
Yes, should be able to do it with Veeam (for that sake Most backup software which integrates with NetApp).
In general, as long as the Cluster/SVM (Secondary-DR) is added to your Backup GUI as 'NAS' Device, you should be able to browse to the Volumes underneath the SVM and select the CIFS_Mirrored volume.
I suggest raise a ticket with Veeam support and they should be able to walk you through, as these options are configurable from the Backup GUI.
Thanks!