cool, just run these 3 in a terminal on your Mikrotik (in winbox or SSH)
:global name=backupfile value=([/system identity get name] . "-" . [/system clock get time])
/system backup save name=$backupfile
/tool fetch address=server_ip src-path=$backupfile user=ftpuser mode=ftp password=ftppass dst-path="/home/ftp-docs/$backupfile" upload=yes
I think you'll get some error from the
fetch command that will help, without an error I'd just be speculating on a few possibilites.