arrayToXml based on: http://www.kerstner.at/en/2011/12/php-array-to-xml-conversion/

array_to_xml.php

<?php
function arrayToXml($array, $rootElement = null, $xml = null) {
  $_xml = $xml;
  if ($_xml === null) {
    $_xml = new SimpleXMLElement($rootElement !== null ? $rootElement : '<command/>');
  }
  foreach ($array as $k => $v) {
    if (is_array($v)) {
      arrayToXml($v, $k, $_xml->addChild($k));
    } else {
      if ($v === NULL) {
        $_xml->addChild($k);
      } else if ($k === 0) {
        $_xml->addChild($v);
      } else {
        $_xml->addChild($k, $v);
      }
    }
  }
  return $_xml->asXML();
}