Retrospect and WD NetCenter Network Drive

[vintagemarketin]

We are a complete Macintosh office. I just implemented a WD Netcenter Network 320GB Drive.
I am unable to run a backup script and get the message:
Can't add that much data to backup set. The limit is 2.0 G.

I am able to DUPLICATE but cannot run a backup script to the Network drive. I read some posts that suggested reformatting the drive to HFS+. I spoke with WD and they told me that the WD NetCenter drive could not be reformatted. Is there a way to backup my data on this drive. It seems silly that Retrospect would set up the application taht way. Wasnt Retospect stictly Mac at one time? It seems liek support for Macintosh computers has slipped into a coma.

Can someone recommend a drive that will allow network backup using Macintosh?