I am trying to do the same by attaching an external USB Hard drive to the NAS. Everything works fine. The drive was detected. I was able to create backup jobs for each of the shared folders in the NAS - using differential backup. Drive was formated in FAT32.
But when I checked the backup result, the backup job didn't create the foldername. It just dumps the whole directory under each shared folder to the drive. And when it goes to the next backup job, the whole drive is wiped out and populated with the content from the next shared folder.
I don't know whether it's because of the way I created the shared folder in the NAS. I didn't put all folders under one shared folder ie. /shared/photos, /shared/ebooks, /shared/etc. Instead, I created the shared folders directly ie. /photos, /ebooks, etc...
So when creating the backup job, the source selected is /photos and the backup folder is /usbdisk1, /ebooks to /usbdisk1. And that goes for the rest of the folders. I can't choose a separate folder under /usbdisk1. Could it be that the target backup is the same /usbdisk1 that it overwrites it for each backup job?
What I want to achieve is to dump the contents of /photos, /ebooks in the NAS to /usbdisk1/photos and /usbdisk1/ebooks in the ext. drive respectively.
Any help is appreciated.