diff --git a/body.go b/body.go
index f7e1ff3..5db0e15 100644
--- a/body.go
+++ b/body.go
@@ -98,12 +98,17 @@ func newDatiGenerali(inv *bill.Invoice) (*datiGenerali, error) {
 		return nil, errors.New("simplified invoices are not currently supported")
 	}
 
+	code := inv.Code
+	if inv.Series != "" {
+		code = fmt.Sprintf("%s-%s", inv.Series, inv.Code)
+	}
+
 	return &datiGenerali{
 		DatiGeneraliDocumento: &datiGeneraliDocumento{
 			TipoDocumento:          codeTipoDocumento,
 			Divisa:                 string(inv.Currency),
 			Data:                   inv.IssueDate.String(),
-			Numero:                 inv.Code,
+			Numero:                 code,
 			DatiRitenuta:           dr,
 			DatiBollo:              newDatiBollo(inv.Charges),
 			ImportoTotaleDocumento: formatAmount(&inv.Totals.Payable),
diff --git a/items.go b/items.go
index 6b19138..c6ae0b5 100644
--- a/items.go
+++ b/items.go
@@ -55,7 +55,7 @@ func generateLineDetails(inv *bill.Invoice) []*dettaglioLinee {
 			PrezzoTotale:        formatAmount(&line.Sum),
 			ScontoMaggiorazione: extractLinePriceAdjustments(line),
 		}
-		if len(line.Taxes) > 0 {
+		if line.Taxes != nil && len(line.Taxes) > 0 {
 			vatTax := line.Taxes.Get(tax.CategoryVAT)
 			if vatTax != nil {
 				d.AliquotaIVA = formatPercentage(vatTax.Percent)