diff --git a/purchase_auto_invoice_method/__init__.py b/purchase_auto_invoice_method/__init__.py
new file mode 100644
index 0000000..a7f437c
--- /dev/null
+++ b/purchase_auto_invoice_method/__init__.py
@@ -0,0 +1,23 @@
+# -*- encoding: utf-8 -*-
+##############################################################################
+#
+#    Purchase Auto Invoice Method module for OpenERP
+#    Copyright (C) 2013 Akretion (http://www.akretion.com)
+#    @author Alexis de Lattre <alexis.delattre@akretion.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+
+from . import purchase
diff --git a/purchase_auto_invoice_method/__openerp__.py b/purchase_auto_invoice_method/__openerp__.py
new file mode 100644
index 0000000..7d440c3
--- /dev/null
+++ b/purchase_auto_invoice_method/__openerp__.py
@@ -0,0 +1,45 @@
+# -*- encoding: utf-8 -*-
+##############################################################################
+#
+#    Purchase auto invoice method module for OpenERP
+#    Copyright (C) 2013 Akretion (http://www.akretion.com)
+#    @author Alexis de Lattre <alexis.delattre@akretion.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+
+
+{
+    'name': 'Purchase Auto Invoice Method',
+    'version': '0.1',
+    'category': 'Purchase',
+    'license': 'AGPL-3',
+    'summary': "Set Invoice Method of PO to 'picking', unless if it's service-only",
+    'description': """
+Purchase Auto Invoice Method
+============================
+
+Set the Invoice Method of the Purchase Order to 'picking' by default. On Purchase Order validation, if it only contains service lines, the Invoice Method is automatically switched to 'order'.
+
+Please contact Alexis de Lattre from Akretion <alexis.delattre@akretion.com> for any help or question about this module.
+    """,
+    'author': 'Akretion',
+    'website': 'http://www.akretion.com',
+    'depends': ['purchase'],
+    'data': [],
+    'images': [],
+    'installable': True,
+    'active': False,
+}
diff --git a/purchase_auto_invoice_method/purchase.py b/purchase_auto_invoice_method/purchase.py
new file mode 100644
index 0000000..2e69e84
--- /dev/null
+++ b/purchase_auto_invoice_method/purchase.py
@@ -0,0 +1,48 @@
+# -*- encoding: utf-8 -*-
+##############################################################################
+#
+#    Purchase Auto Invoice Method module for OpenERP
+#    Copyright (C) 2013 Akretion (http://www.akretion.com)
+#    @author Alexis de Lattre <alexis.delattre@akretion.com>
+#
+#    This program is free software: you can redistribute it and/or modify
+#    it under the terms of the GNU Affero General Public License as
+#    published by the Free Software Foundation, either version 3 of the
+#    License, or (at your option) any later version.
+#
+#    This program is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Affero General Public License for more details.
+#
+#    You should have received a copy of the GNU Affero General Public License
+#    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+##############################################################################
+
+from openerp.osv import orm
+
+
+class purchase_order(orm.Model):
+    _inherit = 'purchase.order'
+
+    _defaults = {
+        'invoice_method': 'picking',
+    }
+
+    def wkf_confirm_order(self, cr, uid, ids, context=None):
+        invoice_method_order_po_ids = []
+        for po in self.browse(cr, uid, ids, context=context):
+            service_only = True
+            for line in po.order_line:
+                if line.product_id.type != 'service':
+                    service_only = False
+            if service_only:
+                invoice_method_order_po_ids.append(po.id)
+        if invoice_method_order_po_ids:
+            self.write(cr, uid, invoice_method_order_po_ids, {
+                'invoice_method': 'order',
+                }, context=context)
+        res = super(purchase_order, self).wkf_confirm_order(
+            cr, uid, ids, context=context)
+        return res