This works:
<form action="http://204.104.133.7/scripts/dc/DCWeb.dll" method="post" TARGET="_blank">

<input type="hidden" name="MfcIsApiCommand" value="Trace">

<input type="hidden" name="Referrer" value="CPCPopup">

<input type="hidden" name="AppLanguage" value="En">

<input type="hidden" name="ItemNumber" value="***TRACKING NUMBER***">

<input type="submit" value="***TRACKING NUMBER***">

</form>
_________________________
Bitt Faulk