Exchange 2010 mailbox server not replicate through delicate Replicate network card

Hi Everybody.

My ogzanition using Exchange 2010 SP2 , we have 6 mailbox with DAG (2 database copies ) config. Each mailbox have 2 network card 1Gbps, and i config as bellow:

Network Card 1 – MAPI

-          - IP: 10.1.2.x

-        -   Subnet mark: 255.255.255.0

-        -   Default Gateway: 10.1.2.1

Netword card 2 – Replicate:

-          - IP: 10.1.2.y

-          - Subnet mard: 255.255.255.0

-          - Default Gateway: Not config

-         - Clear the Register this connection’s addresses in DNS check box

-          - All 6 Replicate card under one VLAN  individual with MAPI VLAN.

Config networ adapter following table

Problem: When mailbox database replicate I saw any traffic through MAPI card not tranfer to Replicate card.

Please help my investigate mistake and reslove problem :(. Thanks !!!