Mule Scope - Message Enricher
<enricher>
<http:outbound-endpoint address="http://xservices.com/rest/servicex" method="POST" contentType="text/xml" exchange-pattern="request-response" doc:name="HTTP_AUDIT" />
<enrich target="#[header:SESSION:requestId]" source="#[xpath:track-response/requestId]" />
</enricher>