ISP1 --- ISP1_IP1:WAN --
                         pfSense --- LAN/172.16.0.1 --------|
ISP2 --- ISP2_IP1:OPT1 -/                                   |
 |                                                outside2/172.16.0.2
 |                                                          |
 |------ ISP2_IP2:static nat(inside,outside):10.0.0.10 -- ASA-5505 -- inside/10.0.0.0
 |                                                          |
 |------ ISP2_IP3:static nat(inside,outside):10.0.0.20 -----|
 |                                                          |
 |------ ISP2_IP4:VPN (outside IP) -------------------------|

route outside2 0 0 172.16.0.1
nat (inside,outside2) source dynamic subnet_inside interface

|.out........pfsense..........in.|.out........ASA.............in.|
public IP > NAT to 172.16.0.0 IP > 172.16.0.0 IP > NAT to 10.0.0.0