We're looking into migrating to Exchange 2010 and hence also upgrading SME to 6.0. I can't seem to find any information on if SME 6, as SME 5, is depending on FCP/iSCSI or if one can use .vmdk-files on a NFS-mounted volume for Exchagne Log/Data.
SME 6.0 depends on iSCSI/FCP protocols as in the previous version. As of now backup of Exchange data on VMDK or NFS disks will not be supported in SME 6.0. This feature is being worked on and will be available in the future releases.