No requirido lineas de typo = Titulo

__init__.py

@@ -1,5 +1,5 @@
 from trytond.pool import Pool
-from . import product, sale, production
+from . import product, sale, production, invoice
 
 __all__ = ['register']
 
@@ -7,6 +7,7 @@ __all__ = ['register']
 def register():
     Pool.register(
         product.Product,
+        invoice.InvoiceLine,
         sale.Sale,
         sale.Line,
         production.Production,

tryton.cfg

@@ -6,6 +6,7 @@ depends:
     sale
     sale_supply_production
     production
+    account_invoice
 xml:
     product.xml
     sale.xml

view/sale_form.xml

@@ -3,6 +3,7 @@
      this repository contains the full copyright notices and license terms. -->
 <data>
     <xpath expr="//field[@name='reference']" position="after">
+	<newline/>
 	<label name="pizza_number"/>
 	<field name="pizza_number"/>
 	<button name="add_pizza"/>