XColumnsSupplier xSuppCols = (XColumnsSupplier)UnoRuntime.queryInterface(
XColumnsSupplier.class, xFormProps );
XNameAccess xCols = xSuppCols.getColumns();
// and update the date column with a NULL value
XColumnUpdate xDateColumn = (XColumnUpdate)UnoRuntime.queryInterface(
XColumnUpdate.class, xCols.getByName( "SALEDATE" ) );
xDateColumn.updateNull();
// then restore the flag
xFormProps.setPropertyValue( "IsModified", aModifiedFlag );
}