Multi-WAN OutBound NAT Not Work

  • Hi Guys,
    I've got a problem, I Have two WAN which route with 32ip each.
    For InBound I used ARP Proxy to active those addresses with no problem.
    But for out bound, I used NAT with BITMask. For the addresses for default gateway have no problem, But I can never use second WAN for outgoing, I found it always use default GW only. Follow with my settings:

    WAN 1  202.XXX.XXX.212 GW 202.XXX.XXX.209  ->  103.XXX.XXX.128 / 27  (Default GW)
    WAN 2  202.XXX.XXX.220 GW 202.XXX.XXX.217  ->  103.XXX.XXX.160 / 27

    OutBound NAT Mapping:
    WAN1  NAT 103.XXX.XXX.128/27  with Bitmask
    WAN2  NAT 103.XXX.XXX.160/27  with Bitmask

    When Use for Outbound, It's used 103.XXX.XXX.128
    but When for Outbound, It's used 202.XXX.XXX.212

    but If I set WAN 2 as default Gateway, It's just reverse. -> 202.XXX.XXX.220 -> 103.XXX.XXX.160

    So, I think something setting may miss or some bugs there which make the firewall  doesn't use the right Gateway.