Server can't see Drobo FS shares

Hi all.

I'm messing about with OS X 10.7 server on a 2Ghz Mac Mini at home and to date all is working fine. The mac is connected to the network via ethernet, as is the Drobo FS.

The Drobo shares mount quite happily on the Macmini desktop, but for some reason they don't appear in any of the server config panes e.g. storage, file sharing, time machine. I'd particulary like to use the Drobo as a destination for the TM backups for the network or even Home directories.

I've got the rest of the server stuff working fine - network logins are working as is file shareing

Any ideas?