diff --git a/app/code/core/Mage/Admin/etc/config.xml b/app/code/core/Mage/Admin/etc/config.xml
index 01aaed5c5..c0c4ca126 100644
--- a/app/code/core/Mage/Admin/etc/config.xml
+++ b/app/code/core/Mage/Admin/etc/config.xml
@@ -67,7 +67,7 @@
             <admin_user_authenticate_after>
                 <observers>
                     <admin_user_login>
-                        <class>Mage_Admin_Model_Observer</class>
+                        <class>admin/observer</class>
                         <method>actionAdminAuthenticate</method>
                     </admin_user_login>
                 </observers>
diff --git a/app/code/core/Mage/Api2/etc/config.xml b/app/code/core/Mage/Api2/etc/config.xml
index 418540224..0eef2c938 100644
--- a/app/code/core/Mage/Api2/etc/config.xml
+++ b/app/code/core/Mage/Api2/etc/config.xml
@@ -79,7 +79,7 @@
             <api_user_authenticated>
                 <observers>
                     <api2_upgrade_key>
-                        <class>Mage_Api2_Model_Observer</class>
+                        <class>api2/observer</class>
                         <method>upgradeApiKey</method>
                     </api2_upgrade_key>
                 </observers>
diff --git a/app/code/core/Mage/Customer/etc/config.xml b/app/code/core/Mage/Customer/etc/config.xml
index a6e3e71ae..853ef82f6 100644
--- a/app/code/core/Mage/Customer/etc/config.xml
+++ b/app/code/core/Mage/Customer/etc/config.xml
@@ -440,7 +440,7 @@
             <customer_customer_authenticated>
                 <observers>
                     <customer_upgrade_password>
-                        <class>Mage_Customer_Model_Observer</class>
+                        <class>customer/observer</class>
                         <method>actionUpgradeCustomerPassword</method>
                     </customer_upgrade_password>
                 </observers>