receiveRequests.xml

<flow name="receiveRequests">
  <http:inbound-endpoint 
    address="http://localhost:9090/picture-request/services/receiveRequest" 
    exchange-pattern="request-response">
      <response>
        <script:transformer>
          <script:script engine="groovy">
            return "Success"
          </script:script>
        </script:transformer>
      </response>
  </http:inbound-endpoint>
  <http:body-to-parameter-map-transformer />
  <script:component>
    <script:script engine="groovy">
      Map map = new HashMap()
      map.put("processDefinitionId", "pictureRequest:1") //the id of the definition
      map.put("imageName", payload.get("imageName"))
      map.put("user", payload.get("user")) 
      return map
    </script:script>
  </script:component>
  <activiti:outbound-endpoint description="createRequestProcess">
    <activiti:create-process />
  </activiti:outbound-endpoint>
</flow>