[Zope-dev] Security Question

Hi all, i have a little security problem. let me explain. root/ index_html foo/ acl_users/ bar/ Image I have a image which could only be view by users with a role named foobar, these users are in acl_users. If i access the image through the web a must authenticate myself for the first time, after that everything works well. But if i want to access the Image via <dtml-var Image> from the index_html in the root-folder a got no access. After searching at Zope.org i tested with <dtml-var "restrictedTraverse('foo/bar/Image')"> but this doesnt works. How do i authenticate myself in foo if i access the folder via dtml. Thanks as P.S.: Sorry for my bad english