diff --git a/base_transaction_id/__init__.py b/base_transaction_id/__init__.py
index 81f72930..ef5622e1 100644
--- a/base_transaction_id/__init__.py
+++ b/base_transaction_id/__init__.py
@@ -22,3 +22,4 @@
 from . import invoice
 from . import sale
 from . import stock
+from . import account_move
diff --git a/base_transaction_id/account_move.py b/base_transaction_id/account_move.py
new file mode 100644
index 00000000..dd64e529
--- /dev/null
+++ b/base_transaction_id/account_move.py
@@ -0,0 +1,37 @@
+# -*- coding: utf-8 -*-
+##############################################################################
+#
+#    Author: Guewen Baconnier
+#    Copyright 2014 Camptocamp SA
+#
+#    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, fields
+
+
+class account_move_line(orm.Model):
+    _inherit = 'account.move.line'
+
+    _columns = {
+        'transaction_ref': fields.char('Transaction Ref.',
+                                       select=True),
+    }
+
+    def copy_data(self, cr, uid, id, default=None, context=None):
+        if default is None:
+            default = {}
+        default['transaction_ref'] = False
+        return super(account_move_line, self).\
+            copy_data(cr, uid, id, default=default, context=context)
diff --git a/base_transaction_id/invoice.py b/base_transaction_id/invoice.py
index c1292595..32f254d8 100644
--- a/base_transaction_id/invoice.py
+++ b/base_transaction_id/invoice.py
@@ -29,8 +29,13 @@ class AccountInvoice(Model):
     _columns = {
         'transaction_id': fields.char(
             'Transaction id',
-            size=128,
-            required=False,
             select=1,
-            help="Transction id from the financial institute"),
+            help="Transaction id from the financial institute"),
     }
+
+    def copy_data(self, cr, uid, id, default=None, context=None):
+        if default is None:
+            default = {}
+        default['transaction_id'] = False
+        return super(AccountInvoice, self).\
+            copy_data(cr, uid, id, default=default, context=context)