Virtual IP (Static NAT) on multiple WAN link running BGP

Hi everyone,

I would like to seek assistance from the experienced forum members on below scenario- 

I have a FG Firewall having 2 BGP peerings and announcing a public pool. The peers are configured as primary/backup in BGP using the attributes (LP/AS prepend) . These 2 interfaces over which the BGP peers are formed are bounded in a zone called "North Zone" 

Now, I have a web server which is using 1 IP from public pool which is being announced over BGP. 

Web Server (10.0.0.1)-----> Fortigate Firewall --- > interface port1---announcing 20.20.20.0/24 to primary peer1

Web Server (10.0.0.1)-----> Fortigate Firewall --->interface port2---announcing 20.20.20.0/24 to secondary peer2

Now, I would like to have a static NAT using VIP for the web server 10.0.0.1 <---->20.20.20.1 

Problem: VIP lets me bind to only 1 interface however in the event primary path is reachable the secondary peer will still have the path to the public pool but this static nat will not work unless I manually create the VIP entry..

I haven't used the "any" option for now as  I had a bad experience with this NAT option in VIP. It hadn't worked but will again give a try to check the flow.

Please provide your valuable inputs on this issue and let me know the solution if you ever encountered this scenario.

Thanks,

Sandeep Jha