<!-- Receive affirmative response -->
<?xml version="1.0"?>
<WfMessage Version="1.0">
  <WfTransport/>
  <WfMessageHeader>
    <Response/>
    <Key>
http://www.Avendorsite.com/WfEngine?Process="ReceiveRFP"
    </Key>
  </WfMessageHeader>
  <WfMessageBody>
    <CreateProcessInstance.Response>
      <ProcessInstanceKey>
  http://www.Avendorsite.com/WfEngine?Process="ProcessRFP1234ABC"
      </ProcessInstanceKey>
    </CreateProcessInstance.Response>
  </WfMessageBody>
</WfMessage>