xmlrpc request error???

Hello all

i am new to codeigniter and getting error while using XMLRPC for sending a specific xml call to a remote server.  I have tried a lot of array examples but not getting the exact out put from my server.

XML Format we required as output.

<?xml version="1.0" encoding="UTF-8" standalone="yes" ?>
<OTA_HotelAvailRQ xmlns="http://www.opentravel.org/OTA/2003/05">
<POS>
<Source>
<RequestorID MessagePassword= "****" ID= "****" Type="CHM"/>
</Source>
</POS>
<AvailRequestSegments>
<AvailRequestSegment>
<HotelSearchCriteria>
<Criterion>
<HotelRef HotelCode="00008382"/>
<StayDateRange Start="2014-12-10" End="2014-12-29">
</StayDateRange>
</Criterion>
</HotelSearchCriteria>
</AvailRequestSegment>
</AvailRequestSegments>
</OTA_HotelAvailRQ>

Already tried structures of array

1. $request = array (
             array('RequestorID'=>array('MessagePassword'=>'testDataCorp','ID'=>'datacorp','Type'=>'CHM')),
                       array('HotelRef'=>array('HotelCode'=>'00008164')),
                            array('StayDateRange'=>array('Start'=>'2016-04-01','End'=>'2016-04-12')));
 
 
 2.$request = array('Source' => array( 'RequestorID'=>array( 'MessagePassword'=> 'testDataCorp', 'ID'=>'datacorp','Type'=>'CHM')                                      ),array('HotelRef'=>array('HotelCode'=>'00008164')),
                     array('StayDateRange'=>array('StayDateRange (Start)'=>'2016-04-01','StayDateRange (End)'=>'2016-04-12'))
 );


3. array(
        array('MessagePassword', 'testDataCorp'),
        array('ID', 'datacorp'),
         array('Type', 'CHM'),
          array('HotelCode', '00008164'),
           array('StayDateRange(Start)', '2016-04-01'),
           array('StayDateRange(End)', '2016-04-12')
);
  

kindly help me so that i can get the exact ouput.

Thanks & Regards
Sandeep Goel