// don't EVER use the 1904 date system
CTWorkbookPr workbookPr = workbook.addNewWorkbookPr();
workbookPr.setDate1904(false);
CTBookViews bvs = workbook.addNewBookViews();
CTBookView bv = bvs.addNewWorkbookView();
bv.setActiveTab(0);
workbook.addNewSheets();
POIXMLProperties.ExtendedProperties expProps = getProperties().getExtendedProperties();
expProps.getUnderlyingProperties().setApplication(DOCUMENT_CREATOR);