HMR to replace codec

Hello;

I am working on an HMR which delete/replace G.722 (payload 9) only if G.729 (payload 18) is present. I worked on this logic but unable to get desired result. I understand their are repercussion of using HMR to replace codec that's why I will test it throughly in the lab first. Can you please let me know the best way to achieve the desired result ?

sip-manipulation

        name                                replace722

        description                             replace 722 with 729

        split-headers

        join-headers

        header-rule

                name                        storeConType729

                header-name                        Content-Type

                action                        store

                comparison-type                        case-sensitive

                msg-type                        request

                methods                        INVITE

                match-value

                new-value

                element-rule

                        name                storet729

                        parameter-name                application/sdp

                        type                mime

                        action                store

                        match-val-type                any