dw.order.SumItem
Usage example:
                                    
var invoice : Invoice = ...;
                                    
var productNet = invoice.productSubTotal.netPrice;
                                    
var serviceNet = invoice.serviceSubTotal.netPrice;
                                    
var grandNet = invoice.grandTotal.netPrice;
                                    
var grandTax = invoice.grandTotal.tax;
                                    
var grandGross = invoice.grandTotal.grossPrice;
                                    
                                    
 # tax breakdown
                                    
for each(taxItem : TaxItem in invoice.grandTotal.taxItems) {
                                    
 var tax : Money = taxItem.amount;
                                    
 var taxGroup : TaxGroup = taxItem.taxGroup;
                                    
 var rate : Double = taxGroup.rate;
                                    
 var caption :String = taxGroup.caption;
                                    
 var taxType :String = taxGroup.taxType;
                                    
}