When I created the monitoring plugin check_storcenter to monitor an EMC/IOMEGA Storcenter back in 2011, it was not necessary to use snmp with authentication, even though when a password was set in the StorCenter administration UI and snmp v3 was used.
Meanwhile three years have passed and of course there are newer firmware versions out there. Now it seems that the newer firmwares (correctly) ask for the snmp authentication.
The new version (20140120) adds support for the snmp authentication by using the new parameter -P (for password).
I also put the plugin on my github account: https://github.com/Napsty/check_storcenter. I'd appreciate public contributions.