I've just had another look at this; likewise the two DSs are on my LAN for now (but will soon be 1000 miles apart).
1. On the destination (DS110j) I created a new share with appropriate privileges to receive the network backup
2. On the DS10j I went to Control Panel then Network Backup, and turned on 'Enable network backup service'; Shared Folder Sync and Time Backup are off.
3. On the source DS (DS112) I went to Backup and Restore (not the Control Panel, but in the drop-down) and used the wizard in the Backup tab to select the DS110j by local IP and used the admin account (*** prev I think I tried my user admin account; maybe it requires the system default admin? ***) to authenticate to the share I created above. I guess it might work with NetBackup, the system default, but I presumed that was created as a container for the backup config? Maybe it is intended to contain the backup itself...
4. I selected an unencrypted and an encrypted share (signified by the surrounding @ symbols) on the source DS112
5. Started sync and... backup failed.
The Network Backup log says:
Network Backup failed to backup task [task name] to [destination]. ( Some files could not be transferred. Possible reasons: 1) backup user has no permission to access the files, 2) files are deleted, 3) illegal file name, 4) too many folders.)
Of those possibilities only (1) makes sense, so perhaps it doesn't work with encrypted shares... more experiments required.
Assuming I eventually get this to work, I will then have to try out scheduling, and going the other way (DS110j to DS112), or using the dynamic hostname and custom port via the WAN with 873/22 forwarding set up instead of LAN IP.
I think perhaps the next thing to try is setting up the share on the destination DS as a Remote Folder (Tools menu in File Station), so I can view the contents via FS on the source D112 and check all the backed-up files are there!
Because both DSs are on the LAN for now (to do the first full sync) I've not had to deal with port forwarding, but understand it will be necessary to open 873 for rsync and 22 for encrypted transfers on both DSs. Re the latter, there is the suggestion to change the SSH port for the purposes of server hardening:viewtopic.php?f=160&t=28853