diff --git a/product/ERP5/Document/CategoryAcquiredMembershipStateConstraint.py b/product/ERP5/Document/CategoryAcquiredMembershipStateConstraint.py
new file mode 100644
index 0000000000000000000000000000000000000000..bc7b3c409b0f9310e5d61701b982085d93bf5f2a
--- /dev/null
+++ b/product/ERP5/Document/CategoryAcquiredMembershipStateConstraint.py
@@ -0,0 +1,53 @@
+##############################################################################
+#
+# Copyright (c) 2008 Nexedi SA and Contributors. All Rights Reserved.
+#                    Romain Courteaud <romain@nexedi.com>
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsability of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# garantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program is Free Software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+##############################################################################
+
+from Products.ERP5Type.mixin.constraint import ConstraintMixin
+from Products.ERP5Type import PropertySheet
+from Products.ERP5Type.Utils import createExpressionContext
+from Products.ERP5Type.Utils import evaluateExpressionFromString
+from Products.ERP5.Document.CategoryMembershipStateConstraint import \
+    CategoryMembershipStateConstraint
+
+class CategoryAcquiredMembershipStateConstraint(
+                          CategoryMembershipStateConstraint):
+  """This method check if the category acquired membership is in a
+  valid workflow state.
+  It can check if an order is linked to validated organisation
+  through source category.
+  """
+  meta_type = 'ERP5 Category Acquired Membership State Constraint'
+  portal_type = 'Category Acquired Membership State Constraint'
+
+  def _getObjectCategoryMembershipList(self, obj, base_category, 
+                                       portal_type_list):
+    """
+    Calculate the object category membership list.
+    Surcharge method from CategoryMembershipStateConstraint.
+    """
+    return obj.getAcquiredValueList(base_category, 
+                                    portal_type=portal_type_list)
diff --git a/product/ERP5/Document/CategoryMembershipStateConstraint.py b/product/ERP5/Document/CategoryMembershipStateConstraint.py
index 4f92b9c1fd8e2f836aec0e0b3331e24182991117..88d50acfd225344ef6bef70e57e524cc71d8c563 100644
--- a/product/ERP5/Document/CategoryMembershipStateConstraint.py
+++ b/product/ERP5/Document/CategoryMembershipStateConstraint.py
@@ -45,6 +45,14 @@ class CategoryMembershipStateConstraint(ConstraintMixin):
 
   _message_id_tuple = ('message_different_state',)
 
+  def _getObjectCategoryMembershipList(self, obj, base_category, 
+                                       portal_type_list):
+    """
+    Calculate the object category membership list.
+    This method was created to allow CategoryAcquiredMembershipStateConstraint
+    class to simply surcharge it.
+    """
+    return obj.getValueList(base_category, portal_type=portal_type_list)
 
   def _checkConsistency(self, obj, fixit=0):
     """Check the object's consistency.
@@ -62,8 +70,8 @@ class CategoryMembershipStateConstraint(ConstraintMixin):
     workflow_state_list = evaluateExpressionFromString(expression_context,
                                                 workflow_state_list_expression)
 
-    membership_list = obj.getValueList(base_category,
-                                       portal_type=portal_type_list)
+    membership_list = self._getObjectCategoryMembershipList(obj, base_category,
+                                                            portal_type_list)
 
     for membership in membership_list:
       current_state = membership.getProperty(workflow_variable)