New Post: CopyIntoItems to update existing document

I checked with Firebug. Here is the post:

<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
<soap:Body>
  <UpdateListItems xmlns="http://schemas.microsoft.com/sharepoint/soap/">
    <listName>Quotes</listName>
      <updates>
        <Batch OnError="Continue">
          <Method ID="1" Cmd="Update">
            <Field Name="Company">New Company</Field>
            <Field Name="ID">79615</Field>
          </Method>
        </Batch>
      </updates>
    </UpdateListItems>
  </soap:Body>
</soap:Envelope>

But in the response back the field is not changed and the original data is written back to the file causing a new version. I really appreciate the help. What else should I be looking for?