PHP Genrate XML Envelope

PHP-Dom-Document

<?php
error_reporting(E_ALL);
ini_set('display_errors', 'on');

$xml = new DOMDocument('1.0', 'utf8');
$xml->formatOutput = true;
$xml->preserveWhiteSpace = false;

$startTag1 = $xml->createElement('startTag1');

function add_dom_child (&$parent, $tag, $value, $type = 'text') {
    global $xml;
    $node = $xml->createElement($tag); 
    $node = $parent->appendChild($node);
    $value = trim(preg_replace('/\s+/', ' ',$value));
    switch($type) {
        case 'cdata':
            $contxt = $xml->createCDATASection($value);
            break;
        case 'bool':
            $value = ($value === true) ? 'TRUE' : 'FALSE';
            $contxt = $xml->createTextNode($value);
            break;
        default:
            $contxt = $xml->createTextNode($value);
            break;
    }
    $contxt = $node->appendChild($contxt);
}

add_dom_child($startTag1, 'Field 1', 'value');
add_dom_child($startTag1, 'Field 2', 'value');
add_dom_child($startTag1, 'Field 3', 'value');

$xml->appendChild($startTag1);

/*Add Child Node*/
$startTag2 = $xml->createElement('startTag2');

$startTag2NodeName = $xml->createElement('startTag2NodeName');

add_dom_child($startTag2NodeName, 'DueDate', 'value');
add_dom_child($startTag2NodeName, 'ProductCode', 'value');
add_dom_child($startTag2NodeName, 'Description', 'value');

$startTag2->appendChild($startTag2NodeName);

$xml->appendChild($startTag2);

$xmlString = $xml->saveXML();
echo $xmlString;

/*Create Object to send*/
 $data_obj = new SoapVar($xmlString, XSD_ANYXML);));