I have to write more about this thema. And I promise to do so if I have time. For now only few words.

The device is constructed and programmed in a way having only one main data volume, Volume_1. So if you want few volumes, I can't be done in native way. So create directory for every data export (volume) you need in the root of the Volume_1. Then export each such a directory using nfs from funplug or by original adminsitrative web interface by samba. Set the rights so user can't do a things you din't allow them.