Hi,
Snapmirror functionality between FAS and AltaVault is not a feature that is available today. If you attend NetApp Insight you'll be able to hear more about the roadmap plans for it, however. As with all future product enhancements, NetApp makes no statement of commitment or contract on product capability until such time it is made formally available via announcement, and release schedules are subject to the discretion of NetApp.
Regards,
Christopher