protected function replaceDataFile($SignedDocData, $signedFile)
{
$data = simplexml_load_string($SignedDocData);
// TODO check that the file is the same file
$old = dom_import_simplexml($data->DataFile);
$new = DataFileInfo::formXml($data->DataFile->asXml(), $signedFile)->getDomElement();
$nodeImport = $old->ownerDocument->importNode($new, true);
$old->parentNode->replaceChild($nodeImport, $old);
return $data->asXML();
}