Hello:
You can look for sogo doc, where you can find a key config which you can add to sogo.conf to display back the OOF section. As /etc/sogo.conf is generated by Zentyal you will need to do a custom stub for that (read public doc regarding stubs)
Nevertheless, please keep in mind that unfortunately, sogo oof will overwrite any mail filter the user might have set up, so this may have unexpected behaviours (that's why it has been removed from default stub)