I have just installed OMV and so far it seems to satisfy all my needs.
I had created a ZFS Mirror under Freenas on the same machine before which i want to keep using while importing a RAID from a Synology NAS on the same machine. Using OMV 2.x is no option as there is no easy way to install zfs on Wheezy and the zfs-plugin for OMV 2.x seems to have been removed.
I also read about the problems with zfs-plugin and OMV > 3.0.69 so I installed that version and the zfs-plugin.
Now while there are no zfs pools imported i can see all filesystems / harddrives under the Filesystems menu point. As soon as I import the zfs pool all other harddrives vanish from the list and only the zfs and its subvolumes are displayed so i cannot configure any other volumes (volumes configured before importing the zfs pool seem to remain accessible e.g. for creating a nfs share).
Is this the normal / desired behaviour or is it a bug?