Hi there,
 
 Looks like I have the same problem, but not sure the situation is the same.
 The device is fgt-60, os 3.0 mr2. A web server on dmz using port mapping vip.
 Originally, I connect only wan1 and everything is ok:
 internal network has access to outside internet, and the web server can be accessed
 from outside and internal(using its public url).
 Then, I try to use both wan ports for load sharing: let all traffic to and from web server go through wan2,
 and internal through wan1.
 The routing monitor page has the followings:(I change the real numbers)
 
    type            network             distance         gateway           interface
 static            0.0.0.0/0                  1          100.100.50.100      ppp0
 static            0.0.0.0/0                  1          100.100.50.100      ppp1
 connected     10.10.10.0/24           0               0.0.0.0             dmz
 connected     100.100.50.100/32    0               0.0.0.0             ppp0
 connected     192.168.1.0/24         0               0.0.0.0             internal
 connected     100.100.100.1/32      0               0.0.0.0             ppp0
 connected     100.100.101.3/32      0               0.0.0.0             ppp1
 
 Before mannual adding any route, web server can be accessed from outside,
 but internal can not access the outside internet.
 I find that wan2 has smaller index no. than wan1 has when using cli command
 ' diag net int list'  (not sure because of this).
 So, I add a policy route:
 
 protocal   0
 incoming interface internal
 source addr 192.168.1.0/255.255.255.0
 destination addr 0.0.0.0/0.0.0.0
 outgoing interface wan1
 gateway addr 0.0.0.0
 
 Then, the internal to wan1 works, and wan2 to dmz still works too.
 Now I am supposed to set up a route for internal <-> dmz, but I did not.
 I thought the packet will go out from wan1 and then come back to wan2,
 and I can simply use its public url to access web server from internal rather than tell
 everyone in the office to use its real private ip. But this does not work. I can not
 use the public url to access web server from internal.
 
 Is my idea basically wrong? Or am I missing something?
 Hope I explain the situation clearly enough.
 Thanks for any response.
 Regards!