Put the configuration onto a key, press it and watch the logs. If you're not familiar with provisioning yet: download a backup from your phone's web-UI and replace an existing key-configuration with this xml. Then simply restore the backup.

getdocu.xml
    <keyConfiguration>
        <lua>
            <code>
                function onKeyUp()
                    debug.log("----------", "e")
                    debug.log(debug.getDocu(sip.invite), "e")
                    debug.log("----------", "e")
                end
            </code>
        </lua>
    </keyConfiguration>