[Zope-CMF] Portal root

[Mikhail Kashkin]

Hi all!

I'm trying to make new skin for CMF site and have a litle trouble.
How I can get root of CMF site for DTML page?

my skin is ZPT based and I want draw a tree site map. 

In main_template call:
[.....]
<div tal:content="structure here/tree_draw" />
[.....]

tree_public contain:
""" tree_public[.py] """
return context.objectValues(['Portal Folder'])

tree_draw.dtml:
<dtml-tree expr="PortalFolder" branches="tree_public" skip_unauthorized="1">
  <a href="&dtml-absolute_url;/admin"><dtml-var title_or_id></a>
</dtml-tree>

PortalFolder is my CMF site, but in this case skin isn't  universal. If I 
change it to portal_url in main_template or tree_draw then it draw only tree 
from context or return nothing. But I wnat see it from root %)
How I can get root?

-- 
Kashkin Mikhail