Uhm, wait, you already have local backups at your primary site, right? And you want to replicate those backup files in the remote readynas?
In this case, since Veeam can only save data in one repository per job, is to go on saving backups locally, and then replicate backup files to the remote storage via replication software like rsync. Search in these forums, there are many examples about how to use rsync.
EMEA Evangelist @ Veeam Software
Veeam VMCE #1