diff --git a/addons/sale/sale.py b/addons/sale/sale.py
index 24bf36fab9c..bd5eab6c943 100644
--- a/addons/sale/sale.py
+++ b/addons/sale/sale.py
@@ -319,6 +319,9 @@ class SaleOrder(models.Model):
                 invoice.type = 'out_refund'
                 for line in invoice.invoice_line_ids:
                     line.quantity = -line.quantity
+            # Use additional field helper function (for account extensions)
+            for line in invoice.invoice_line_ids:
+                line._set_additional_fields(invoice)
             # Necessary to force computation of taxes. In account_invoice, they are triggered
             # by onchanges, which are not triggered when doing a create.
             invoice.compute_taxes()