Wan Optimization over Tunnel IPSEC

Hello, I have 2 distant sites connected with Fortigate 51E with 2 WAN connection and 2 tunnel IPESEC with OSPF. On WAN 1 ( tunnel 1) I would like activate WAN Optimization because I have traffic video. It's possible saving bandwidth (Between 2 Fortigate)? I already actived wan optimization active / active , passive/active , active,passive, passive/passive but it not working and in Default profile I have selected any protocol and byte caching.

For each tunnel I have 2 policies. WAN 2 it's only for surfing on Internet.

I'm student and I'm in internship, sorry for my bad English

Thank you in advance.