How to Recover whole lost volume?

We left our computer backing itself up overnight - only to come down this morning and discover that our entire volume had disappeared from the external hard drive! FileSalvage can see files on the drive, but it helpfully calls them all 'file.doc' , 'file.html' etc., and we can't stand the thought of 'recovering' gigabytes of data by scrutinising the preview box for hints as to what the file was, then having to rename it, re-file it, etc., through thousands of files!
TechTool Pro can't see the volume at all either. It can only see the drive. Anyone know of a decent data recovery programme that can get the volume back again? It hasn't been deleted, nor the drive formatted, and the computer was happily backing-up to it last night.

it sounds like you might have to send it out to a service to recover it....bummer