diff --git a/addons/purchase/purchase.py b/addons/purchase/purchase.py
index c950c852261..b0f10d3f71f 100644
--- a/addons/purchase/purchase.py
+++ b/addons/purchase/purchase.py
@@ -740,7 +740,7 @@ class purchase_order(osv.osv):
         return [('state', '=', 'draft')]
 
     def create_send_note(self, cr, uid, ids, context=None):
-        return self.message_post(cr, uid, ids, body=_("Request for quotation <b>created</b>."), subtype="new", context=context)
+        return self.message_post(cr, uid, ids, body=_("Request for quotation <b>created</b>."), subtype_xml_id="purchase_subtype_new", context=context)
 
     def confirm_send_note(self, cr, uid, ids, context=None):
         for obj in self.browse(cr, uid, ids, context=context):
@@ -758,20 +758,20 @@ class purchase_order(osv.osv):
     def invoice_send_note(self, cr, uid, ids, invoice_id, context=None):
         for order in self.browse(cr, uid, ids, context=context):
             for invoice in (inv for inv in order.invoice_ids if inv.id == invoice_id):
-                self.message_post(cr, uid, [order.id], body=_("Draft Invoice of %s %s is <b>waiting for validation</b>.") % (invoice.amount_total, invoice.currency_id.symbol), subtype="pending", context=context)
+                self.message_post(cr, uid, [order.id], body=_("Draft Invoice of %s %s is <b>waiting for validation</b>.") % (invoice.amount_total, invoice.currency_id.symbol), subtype_xml_id="purchase_subtype_pending", context=context)
 
     def shipment_done_send_note(self, cr, uid, ids, context=None):
-        self.message_post(cr, uid, ids, body=_("""Shipment <b>received</b>."""), subtype="received", context=context)
+        self.message_post(cr, uid, ids, body=_("""Shipment <b>received</b>."""), subtype_xml_id="purchase_subtype_received", context=context)
 
     def invoice_done_send_note(self, cr, uid, ids, context=None):
-        self.message_post(cr, uid, ids, body=_("Invoice <b>paid</b>."), subtype="paid", context=context)
+        self.message_post(cr, uid, ids, body=_("Invoice <b>paid</b>."), subtype_xml_id="purchase_subtype_paid", context=context)
 
     def draft_send_note(self, cr, uid, ids, context=None):
-        return self.message_post(cr, uid, ids, body=_("Purchase Order has been set to <b>draft</b>."), context=context)
+        return self.message_post(cr, uid, ids, body=_("Purchase Order has been set to <b>draft</b>."), subtype_xml_id="purchase_subtype_new", context=context)
 
     def cancel_send_note(self, cr, uid, ids, context=None):
         for obj in self.browse(cr, uid, ids, context=context):
-            self.message_post(cr, uid, [obj.id], body=_("Purchase Order for <em>%s</em> <b>cancelled</b>.") % (obj.partner_id.name), subtype="cancelled", context=context)
+            self.message_post(cr, uid, [obj.id], body=_("Purchase Order for <em>%s</em> <b>cancelled</b>.") % (obj.partner_id.name), subtype_xml_id="purchase_subtype_cancelled", context=context)
 
 purchase_order()
 
diff --git a/addons/purchase/purchase_data.xml b/addons/purchase/purchase_data.xml
index a84564b2360..aa62e84e19d 100644
--- a/addons/purchase/purchase_data.xml
+++ b/addons/purchase/purchase_data.xml
@@ -49,37 +49,28 @@ You can also manage purchase requisitions, see also the Purchase Settings.</fiel
             model="ir.values"
             name="set"/>
         
-        <record id="mail.mail_subtype_new" model="mail.message.subtype">
+        <record id="mail.purchase_subtype_new" model="mail.message.subtype">
             <field name="name">new</field>
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
+            <field name="res_model">purchase.order</field>
             <field name="default" eval="False"/>
         </record>
-        <record id="mail.mail_subtype_paid" model="mail.message.subtype">
+        <record id="mail.purchase_subtype_paid" model="mail.message.subtype">
             <field name="name">paid</field>
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
+            <field name="res_model">purchase.order</field>
         </record>
-        <record id="mail.mail_subtype_pending" model="mail.message.subtype">
+        <record id="mail.purchase_subtype_pending" model="mail.message.subtype">
             <field name="name">pending</field>
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
+            <field name="res_model">purchase.order</field>
             <field name="default" eval="False"/>
         </record>
-        <record id="mail.mail_subtype_received" model="mail.message.subtype">
+        <record id="mail.purchase_subtype_received" model="mail.message.subtype">
             <field name="name">received</field>
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
+            <field name="res_model">purchase.order</field>
         </record>
-        <record id="mail.mail_subtype_cancelled" model="mail.message.subtype">
+        <record id="mail.purchase_subtype_cancelled" model="mail.message.subtype">
             <field name="name">cancelled</field>
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
+            <field name="res_model">purchase.order</field>
             <field name="default" eval="False"/>
         </record>
-        <record id="mail.mail_subtype_email" model="mail.message.subtype">
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
-        </record>
-        <record id="mail.mail_subtype_comment" model="mail.message.subtype">
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
-        </record>
-        <record id="mail.mail_subtype_other" model="mail.message.subtype">
-            <field name="model_ids" eval="[(4,ref('purchase.model_purchase_order'))]"/>
-        </record>
     </data>
 </openerp>