there is some free software out there. i will see what i have downloaded.
in an enterprise environment, it would be best to have a file server that runs incremental backups everynight, as opposed to a NAS. i try to stay away from nas for certain reasons.
too bad you didnt purchase the driver sooner. WD recently settled a class action lawsuit where some WD owners got backup software for free.
edit: here is a free backup software i downloaded awhile back. i have never used it, so no guarantees.
also try this page, there is tons of free software here, just look thru it