messageSendSingle

<soapenv:Envelope 
    xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/" 
    xmlns:ecm="http://ecircle.com/developer/ecmapi">
   <soapenv:Header/>
   <soapenv:Body>
      <ecm:messageSendSingle>
         <messageId>2</messageId>
         <recipientId>7</recipientId>
        <additionalContent>
            <!--Zero or more repetitions:-->
            <parameters>
               <name>subject</name>
               <value>This is a subject</value>
            </parameters> 
         </additionalContent> 
      </ecm:messageSendSingle>
   </soapenv:Body>
</soapenv:Envelope>