[Zope] Last Modified Entry for Methods

Hi all, I use the bobobase property(?) to display when a document has been edited. <dtml-var bobobase_modification_time fmt="%d.%m.%Y"> But this works so far only for folders and not for methods. Or is there any opportunity to get the "last modified" entry from the index_html Method? It is listed in the standard manage-view... Martin