[Serusers] How can I distinguish 487 and 603 reply?

[Zhang Wei]

hello,Jan
    I  meet some  trouble when I use SER .I hope that when the call timeouts or is declined by the callee  the call would be forward to SEMS.  In my ser.cfg ,I wrote :
       if (method=="INVITE")
      {
           t_on_failure("1");
      } 
    But when the caller cancels the call,487 reply the callee sends  aslo  make INVITE enter the failure_route. I don't export it. So how can I distinguish 487 and 603 ?

    Thanks for  your help

Wei