Hi Mcatanzaro,
My requirement is to take only firewall configuration backup "show configuration". So I wouldn't use system backup for that.
Yes, I created script (backupscript.sh) in /home/admin directory and used in crontab.
I edited crontab with below line.
20 06 7 * * /home/admin/backupscript.sh
Assigned full permission to the script file. User is admin, who is executing the script having full rights.
Only problem was that crontab entry got removed automatically if gateway reboots.
I tried to use job scheduler but it doesn't have option to transfer file to FTP server. It has only option to send output to email.