diff --git a/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km/Base_isReferenceUnique.xml b/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km/Base_isReferenceUnique.xml
new file mode 100644
index 0000000000000000000000000000000000000000..4d794312446a36752f3214708cb0de8d5aba702e
--- /dev/null
+++ b/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km/Base_isReferenceUnique.xml
@@ -0,0 +1,142 @@
+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="PythonScript" module="Products.PythonScripts.PythonScript"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>Script_magic</string> </key>
+            <value> <int>3</int> </value>
+        </item>
+        <item>
+            <key> <string>_bind_names</string> </key>
+            <value>
+              <object>
+                <klass>
+                  <global name="NameAssignments" module="Shared.DC.Scripts.Bindings"/>
+                </klass>
+                <tuple/>
+                <state>
+                  <dictionary>
+                    <item>
+                        <key> <string>_asgns</string> </key>
+                        <value>
+                          <dictionary>
+                            <item>
+                                <key> <string>name_container</string> </key>
+                                <value> <string>container</string> </value>
+                            </item>
+                            <item>
+                                <key> <string>name_context</string> </key>
+                                <value> <string>context</string> </value>
+                            </item>
+                            <item>
+                                <key> <string>name_m_self</string> </key>
+                                <value> <string>script</string> </value>
+                            </item>
+                            <item>
+                                <key> <string>name_subpath</string> </key>
+                                <value> <string>traverse_subpath</string> </value>
+                            </item>
+                          </dictionary>
+                        </value>
+                    </item>
+                  </dictionary>
+                </state>
+              </object>
+            </value>
+        </item>
+        <item>
+            <key> <string>_body</string> </key>
+            <value> <string>"""\n
+  External validator for login_form\n
+  that checks that reference is unique into the system.\n
+"""\n
+kw={\'reference\': editor,\n
+    \'portal_type\': [\'Person\', \'Credential Request\']}\n
+email = context.portal_catalog.getResultValue(**kw)\n
+if email is not None:\n
+  return 0\n
+return 1\n
+</string> </value>
+        </item>
+        <item>
+            <key> <string>_code</string> </key>
+            <value>
+              <none/>
+            </value>
+        </item>
+        <item>
+            <key> <string>_params</string> </key>
+            <value> <string>editor, request</string> </value>
+        </item>
+        <item>
+            <key> <string>_proxy_roles</string> </key>
+            <value>
+              <tuple>
+                <string>Manager</string>
+              </tuple>
+            </value>
+        </item>
+        <item>
+            <key> <string>errors</string> </key>
+            <value>
+              <tuple/>
+            </value>
+        </item>
+        <item>
+            <key> <string>func_code</string> </key>
+            <value>
+              <object>
+                <klass>
+                  <global name="FuncCode" module="Shared.DC.Scripts.Signature"/>
+                </klass>
+                <tuple/>
+                <state>
+                  <dictionary>
+                    <item>
+                        <key> <string>co_argcount</string> </key>
+                        <value> <int>2</int> </value>
+                    </item>
+                    <item>
+                        <key> <string>co_varnames</string> </key>
+                        <value>
+                          <tuple>
+                            <string>editor</string>
+                            <string>request</string>
+                            <string>kw</string>
+                            <string>_apply_</string>
+                            <string>_getattr_</string>
+                            <string>context</string>
+                            <string>email</string>
+                            <string>None</string>
+                          </tuple>
+                        </value>
+                    </item>
+                  </dictionary>
+                </state>
+              </object>
+            </value>
+        </item>
+        <item>
+            <key> <string>func_defaults</string> </key>
+            <value>
+              <none/>
+            </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>Base_isReferenceUnique</string> </value>
+        </item>
+        <item>
+            <key> <string>warnings</string> </key>
+            <value>
+              <tuple/>
+            </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>
diff --git a/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km_theme/login_form/your_default_email_text.xml b/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km_theme/login_form/your_default_email_text.xml
index 8d1309090dd22ae9c46c00881e0b6e94e53fb5c8..9d3e2fac951d5364ab666eeece2f0df3ac98d966 100644
--- a/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km_theme/login_form/your_default_email_text.xml
+++ b/bt5/erp5_km/SkinTemplateItem/portal_skins/erp5_km_theme/login_form/your_default_email_text.xml
@@ -11,6 +11,15 @@
             <value>
               <list>
                 <string>enabled</string>
+                <string>external_validator</string>
+              </list>
+            </value>
+        </item>
+        <item>
+            <key> <string>delegated_message_list</string> </key>
+            <value>
+              <list>
+                <string>external_validator_failed</string>
               </list>
             </value>
         </item>
@@ -24,7 +33,7 @@
               <dictionary>
                 <item>
                     <key> <string>external_validator_failed</string> </key>
-                    <value> <string>The input failed the external validator.</string> </value>
+                    <value> <string>Email is already used into the system. Please try new one.</string> </value>
                 </item>
               </dictionary>
             </value>
@@ -81,6 +90,12 @@
                     <key> <string>enabled</string> </key>
                     <value> <int>1</int> </value>
                 </item>
+                <item>
+                    <key> <string>external_validator</string> </key>
+                    <value>
+                      <persistent> <string encoding="base64">AAAAAAAAAAM=</string> </persistent>
+                    </value>
+                </item>
                 <item>
                     <key> <string>field_id</string> </key>
                     <value> <string>your_default_email_text</string> </value>
@@ -112,4 +127,17 @@
       </dictionary>
     </pickle>
   </record>
+  <record id="3" aka="AAAAAAAAAAM=">
+    <pickle>
+      <global name="Method" module="Products.Formulator.MethodField"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>method_name</string> </key>
+            <value> <string>Base_isReferenceUnique</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
 </ZopeData>
diff --git a/bt5/erp5_km/bt/revision b/bt5/erp5_km/bt/revision
index 3a2ac0e3fa68bbe9eded20380ed1c7ffcb27c6cb..9b21444cdb612fa3ae69eee9f48e31d937a3531a 100644
--- a/bt5/erp5_km/bt/revision
+++ b/bt5/erp5_km/bt/revision
@@ -1 +1 @@
-1701
\ No newline at end of file
+1703
\ No newline at end of file