The implication of Todd's post is that you can't do Volume Replication on a NAS volume. Volume replication is only for block level volumes (iscsi). You are going to need to use Data Replication using the first procedure he outlined.
Im trying to get a DL320s woking woth the DSS USB DOM. Im also using the P800. When it boots i only get an error message on screen. How did you manage to boot from the USB DOM?