freeswitch/conf/testing/directory/default.xml

<domain name="$${domain}">

  <params>
    <param name="dial-string" value="{^^:sip_invite_domain=${dialed_domain}:presence_id=${dialed_user}@${dialed_domain}}${sofia_contact(*/${dialed_user}@${dialed_domain})},${verto_contact(${dialed_user}@${dialed_domain}"/>
    <param name="jsonrpc-allowed-methods" value="verto"/>
  </params>
  
  <variables>
    <!--<variable name="record_stereo" value="true"/>-->
  </variables>
  
  <groups>
    <group name="default">
      <users>
	<X-PRE-PROCESS cmd="include" data="default/*.xml"/>
      </users>
    </group>
  </groups>
  
</domain>