FortiADC doesn't pass users remote IP

We have a FortiADC in our production, it is running well, except it cannot pass users remote IP to the servers in the cluster, especially for Layer7 load balancing. 

We have opened a ticket, but the support center said we cannot get the remote IP on Layer7 load balancing. We asked for a workaround, they said there is no workaround because it is by design.

We really need to get the remote IP on layer7 load balancing. So, how to overcome this? How can we request a feature to enable us to get remote UP on layer7?

Thank you