Acme Packet HMR for manipulating incoming errors

Hi all!

Because of our call system we are unable to receive 503 Service Unavailible from provider and we need to change this errror for another code, for example 480 Unavailible.

Is this HMR correct?

sip-manipulation

        name                                    503_Sip_Error_manipulate

        description                            

        split-headers                          

        join-headers                           

        header-rule

                name                                    ManipulateErrors

                header-name                             From

                action                                  manipulate

                comparison-type                         case-sensitive

                msg-type                                any

                methods                                

                match-value                             503

                new-value                               480:Unavailable

        last-modified-by                        admin@console

        last-modified-date                      2015-09-22 09:07:15

As I understand I need to apply it as in-manipulationid on my providers session-agent.

But it doesn't work. What's wrong with it?