fmt.setTimeZone(TimeZone.getTimeZone("UTC"));
String nowStr = fmt.format(signatureConfig.getExecutionTime());
LOG.log(POILogger.DEBUG, "now: " + nowStr);
SignatureTimeDocument sigTime = SignatureTimeDocument.Factory.newInstance();
CTSignatureTime ctTime = sigTime.addNewSignatureTime();
ctTime.setFormat("YYYY-MM-DDThh:mm:ssTZD");
ctTime.setValue(nowStr);
Element n = (Element)document.importNode(ctTime.getDomNode(),true);
List<XMLStructure> signatureTimeContent = new ArrayList<XMLStructure>();
signatureTimeContent.add(new DOMStructure(n));
SignatureProperty signatureTimeSignatureProperty = getSignatureFactory()
.newSignatureProperty(signatureTimeContent, "#" + signatureConfig.getPackageSignatureId(),
"idSignatureTime");