OSSV (Open systems SnapVault) is used to backup VMFS data not hosted on a NetApp filer.
So like already stated you can use SMVI (in VSC 2.0) or just do al normal filer snapshot/snapvault. Changes that your VM is corrupt are a bit higher with the last method.
With NFS you could just can make a flexclone and copy the file back to restore, with a VMFS lun there is the option to do a lun clone and use that to copy the VM back. Otherwise you can use SnapVault to restore the entire lun.
SMVI makes it easy to restore a VM from local snapshot, but there is no integration with SnapVault, so no easy restore from a SnapVault destination like is possible with SnapManager for SQL and SharePoint.
I hope your question was answered. If not, then yes it is possible to use snapvault for lun backup and restore. the restore is a little painful, but to restore , you basically have to restore to a different volume on the source filer, make it read-write, since the backup of the lun is read-only. then you would have to mount the lun to your ESX host, then restore the VM files e.g. vmdk's, vmx files to the respective folders. So it is more steps when you compare to NFS datastores and snapvault, but it does work