private static void setHSSFCellPtgs(HSSFCell cell, Ptg[] ptgs) {
//tricky! must be after the dummyCell construction or the under aggregate record will not
//be consistent in sheet and cell
cell.setCellType(Cell.CELL_TYPE_FORMULA);
FormulaRecordAggregate agg = (FormulaRecordAggregate) new HSSFCellHelper((HSSFCell)cell).getCellValueRecord();
FormulaRecord frec = agg.getFormulaRecord();
frec.setOptions((short) 2);
frec.setValue(0);
//only set to default if there is no extended format index already set
if (agg.getXFIndex() == (short)0) {
agg.setXFIndex((short) 0x0f);
}