function createIdentifierNode($doc, $workOrProduct, $idType, $id)
{
$deployment = $this->getDeployment();
$productIdentifierNode = $doc->createElementNS($deployment->getNamespace(), "{$workOrProduct}Identifier");
// ID type (mandatory)
$productIdentifierNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), "{$workOrProduct}IDType", $idType));
// ID (mandatory)
$productIdentifierNode->appendChild($node = $doc->createElementNS($deployment->getNamespace(), 'IDValue', $id));
return $productIdentifierNode;
}