In dialplan I set ringback variable

      <extension name="setRingback" continue="true">

         <condition>

            <action application="set" data="ringback=${us-ring}"/>

         </condition>

      </extension>

And diaplan terminate call on extension

<extension name="agent_login">

   <condition field="${destination_number}" expression="^agent_login$">

      <action application="set"

              data="ignore=${callcenter_config(agent set status ${caller_id_number}@${sip_to_host} 'Available')}"

              inline="true"/>

      <action application="ring_ready"/>

      <action application="pre_answer"/>

      <action application="sleep" data="2500"/>

      <action application="answer"/>

      <action application="sleep" data="700"/>

   </condition>

</extension>

But ringback is not generaded. Why is it posible?

Sergey