[Zope] domains (acl_users) and access via proxy

Hello, Our users are acessing to the Zope server thru corporate (ministers) proxys. I can't get the "domains" working, while trying (agriculture.gouv.fr, gouv.fr, fr) even with simple one. I'm suspecting some changes in the REQUEST made by the corporate proxys. Is there any doc about what REQUEST variable is used in the "domains" restriction ? (I have a HTTP_FORWARDED with the *proxy* name (unfortunately without the .gouv.fr). I can't find anything on the site and the list either. Thanks in advance.