Imaging Data Store

We have just set up new DS 6.9 Server with a separate server to host all of our RIPs and Images. My question is how do you setup a distribute image job if the Images are on a seperate server. Whenever I create the job it tells me that the image file is not in the same data store as the express share. I tried using UNC but it didn't like that. I tried mapping a drive to that share and it didn't like that either. Need help here!!