Backing up Files on a ZyXel NSA 325 server

How do I backup files on an ZyXel NSA 325, NAS server, to an off site location on the internet such as a cloud service e.g. Dropbox, Google drive, etc., or other Internet location. I have heard this is possible. I have tried Backup Planner, a package that comes with the server, and it does not seem to have this facility.

I would like to back-up specific folders and files held on the NSA 325 on a scheduled or automatic basis. Are there any packages or software that would do this, even third party? Total backup is expected to be 50-100GB

Any help would be greatly appreciated.