According to the help documentation for SDM If you have configured NAT and are now configuring your firewall, you must configure the firewall so that it permits traffic from your public IP address. To do this you must configure an ACL. To configure an ACL permitting traffic from your public IP address...
But I got two external WAN interfaces with load balance configuration on round robin basis
What else do I have to do for each port/inside ip pair to make available to be initiated through either WAN interface and make the ensuring return traffic flow through only the originating WAN port?