[Zope] mailhost location problem

[Ben Avery]

Hi,

since restructuring my zope objects to tidy up the project's root 
folder, I've been able to get objects working, but others not.

I have put things like some zsql and python methods in a folder called 
'helpers', so I can call a python method which spits out a dropdown HTML 
element, from any page as <dtml-var "helpers.category_dropdown()">

but I can't seem to make a <dtml-sendmail ..> tag work, however I refer 
to the mailhost object living in helpers.
I've tried <dtml-sendmail mailhost="helpers/MailHost">, 
helpers.MailHost, and everything else I can think of, but it complains 
it still can't find it.
Could anyone tell me how to refer to this mailhost object?

TIA

Ben Avery
YouthNet UK

(p.s. Zope 2.5.1, Python 2.1.3, Solaris 7)