How change the "uri-host" in "To" if SDP contains a=inactive (HOLD)

Hi,

My proposal is to create an HMR that change the "uri-host" in "To" if SDP contains --> a=inactive. This situation appears when I push the button HOLD from a phone (PBX = Unigy IPC). I need to change in "uri-host" the SBC IP address (172.18.169.166) for the Cisco Call Manager IP address (172.23.255.133). Apparently Unigy IPC (PBX) request the HOLD to SBC instead Cisco Call Manager.

Unfortunatelly, this HMR is not working:

sip-manipulation

        name                                    Change_urihost_HOLD

        description                            

        split-headers                          

        join-headers                           

        header-rule

                name                                    checkhold_hr

                header-name                             Content-Type

                action                                  store

                comparison-type                         case-sensitive

                msg-type                                request

                methods                                 INVITE

                match-value                            

                new-value                              

                element-rule

                        name                                    checkhold_er

                        parameter-name                          application/sdp