[Zope] Problem with dtml-sendmail

we wrote an email form that performs a POST on a python script. This python script calls a dtml-method with the <dtml-sendmail>. The dtml-sendmail does not find the MailHost if it is not in the same folder. So I have to create a separate MailHost in the same folder and everything is fine. Acquisition otherwise works fine, the standard_html_header is found and included. So why does Acuqisition not work for dtml-sendmail? Any ideas? Markus