Mac OS X 10.7.2 Lion Client that bind to replica OD 10.7.2 Server refuse to failover to look at Mast

Hi All, I got a tricky situation here. My Setup Mac OS X Master OD 10.7.2 Server Mac OS X Replica OD 10.7.2 Server Clients are bind to the replica Mac OS X server( 10.7.2) for MCX management and Bind to AD for Authentication. The tricky part comes, When I shut down the replica Mac OS X server (10.7.2) to test whether the Mac Client (10.7.2) will failover and point it to the Master OD (10.7.2 ) Server. It refuse to failover. Like wise , I get the Mac Client (10.7.2) to bind to the master OD Server , and I shut down the Master OD server and test whether the Mac Client will failover and point it to the replica OD server for MCX. It refuse to failover and have the famous red light. But If I do Manual Binding (work like a charm) I will go into Directory Utility and manually bind OD and AD , it work like a charm. The Client will automatically do failover and point it to the replica or Master , depend on which OpenDirectory it bind to . Single Command of authenticated binding and using a binding script still produce the same result dsconfigldap -f -a "${ODM_SERVER}" -c "${COMPUTER_ID}" -u "${ADMIN_LOGIN}" -p "${ADMIN_PWD}" My binding script (took from DeployStudio Bind OD script ) http://pastebin.com/ncXvAAgZ I am at a lost. Any suggestion will be good. Thanks Roy