A Land Far Away

Can anyone recommend any file recovery software that's compatible with network attached storage units, specifically a SnapServer 4100 running Raid 5? There's been times when the backup client that runs on the workstations at a small remote office lock up and close, leaving files unprotected from asshattery until their rebooted. Twice now, I've had people delete stuff they shouldn't only to find it wasn't backed up.

Is there anything I can use to recover deleted files off a NAS raid array??

Thanks.

Kate