Need help adding AVP code 256 "AKA-Pseudonym"

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Hi, I am trying to add a new AVP value=256 (AKA-Pseudonym) by adding following in Dictionary.xml file

<avp name="AKA Pseudonym-Id" code="256" mandatory="must" may-encrypt="yes" vendor-id="TGPP">
                        <type type-name="OctetString"/>
                </avp>

I am having no success. Can someone kindly help me out here? Couldn't find an option to upload my pcap here.