boton enviar por correo visible

__openerp__.py

@@ -7,6 +7,7 @@
 'data':[
     'views/email_template_view.xml',
     'views/res_partner_view.xml',
+    'views/sale_view.xml',
     ],
 'depends':[
     'base',

views/sale_view.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<openerp>
+  <data>
+    <record id="sale_view_form" model="ir.ui.view">
+      <field name="name">sale_view_form</field>
+      <field name="model">sale.order</field>
+      <field name="inherit_id" ref="sale.view_order_form"/>
+      <field name="arch" type="xml">
+        <button name="action_quotation_send" position="replace">
+          <button name="action_quotation_send" string="Send by Email" type="object" class="oe_highlight" groups="base.group_user" invisible="0"/>
+        </button>
+      </field>
+    </record>
+  </data>
+</openerp>