[Zope] sidebar sorting

Hi, I have following DTML method for a sidebar construction: <ul> <dtml-in expr="objectValues('Folder')" sort="_.[sort]"> <li><a class="sidemenu" href="&dtml-absolute_url;"><dtml-var title_or_id></a><br></li> </dtml-in> </ul> I set a property named 'sort' to every folder, but my code doesn't work. How can I achieve arbitrary sorting for the menu? Oliver