link backup Internet Fortigate 5.6.1

hi 

i have fortigate 100E with os 5.6.1 

and two link internet from one PSP one master(active) and another Backup (Passive). (PSP Setting IP SLA on two Links)

َAfter the search i realized used Dead gateway But dead gateway do not Support on Fortios 5.61

please help me How to Setup this