[Zope] using DTML-tree within formulator

Hello All, For a project i need to use formulator. I created a form and used the exported XML in my own silva extension that works. But now i need to have some logic into my form :). I need to retrieve a list of the contents from a certain folder and put this information into a listfield. But how can I do this? I didnt find a good tutorial on how to accomplish this with tal Yours sincerely, J.somhorst