The following snippet have to be added to the config.xml under the frontend (for FE-events) – or the adminhtml (for BE-Events) – tag: <events> <event_name> <observers> <observer_unique_config_name> <!– singleton or model –> <type>singleton</type> <class>Namespace_Modul_Model_Modelname</class> <method>functionToCallOnModelClassInstance</method> </observer_unique_config_name> </observers> </event_name> </events>