Description:
------------
Using latest SDO checked out from PECL and proper versions of the WSDL xsds, when I serialize the wsdl object I get WSDL with the same element twice

I can supply a zip file with the client program and wsdls

Reproduce code:
---------------
$xmldas = SDO_DAS_XML::create('wsdl/wsdl-all.xsd');

$wsdl_doc 			= $xmldas->createDocument();
$wsdl				= $wsdl_doc->getRootDataObject(); // this is the <definitions> element

$class_name="Donkey";
$ops = array('Punch'=>'sausages');

/********************************************************************************
* Create the <portType> element
********************************************************************************/
$portType 					= $wsdl->createDataObject('portType');
$portType->name 			= "{$class_name}PortType";
foreach ($ops as $op_name => $params) {
	$portType_operation 		= $portType->createDataObject('operation');
	$portType_operation->name 	= $op_name;
	$pt_input 					= $portType_operation->createDataObject('input');
	$pt_input->message 			= "{$op_name}Request";
	$pt_output 					= $portType_operation->createDataObject('output');
	$pt_output->message 		= "{$op_name}Response";
}

$str = $xmldas->saveString($wsdl_doc,2);
echo $str;

Expected result:
----------------
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://schemas.xmlsoap.org/wsdl/" xsi:type="tDefinitions" xmlns:tns2="" xmlns:tns="http://schemas.xmlsoap.org/wsdl/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <portType name="DonkeyPortType">
    <operation name="Punch">
      <input message="tns2:PunchRequest"/>
      <output message="tns2:PunchResponse"/>
    </operation>
  </portType>
</definitions>



Actual result:
--------------
<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://schemas.xmlsoap.org/wsdl/" xsi:type="tDefinitions" xmlns:tns2="" xmlns:tns="http://schemas.xmlsoap.org/wsdl/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <portType name="DonkeyPortType">
    <operation name="Punch">
      <input message="tns2:PunchRequest"/>
      <output message="tns2:PunchResponse"/>
      <output message="tns2:PunchResponse"/>
      <input message="tns2:PunchRequest"/>
    </operation>
  </portType>
</definitions>