I guess many peoples calls getLastRequest and it returns nothing. "Heey where is the my last request". Now we will see our request, when you created a SoapClient instance, you should give a option parameter as below :
<?php
$option=array('trace'=>1);
$client=new SoapClient('some.wsdl',$option);
try{
$client->aMethodAtRemote();
}catch(SoapFault $fault){
echo 'Request : <br/><xmp>',
$client->__getLastRequest(),
'</xmp><br/><br/> Error Message : <br/>',
$fault->getMessage();
}
?>
"trace" parameter enables output of request. Now, you should see SOAP request.