function createRootNode($doc, $rootNodeName)
{
$deployment = $this->getDeployment();
$rootNode = $doc->createElementNS($deployment->getNamespace(), $rootNodeName);
$rootNode->setAttributeNS('http://www.w3.org/2000/xmlns/', 'xmlns:xsi', $deployment->getXmlSchemaInstance());
$rootNode->setAttribute('xsi:schemaLocation', $deployment->getNamespace() . ' ' . $deployment->getSchemaFilename());
return $rootNode;
}