[ZPT] ZPT, manage_workspace from product

[Michael Johnson]

I have a product, which has a member variable which is a ZPTFile object.  I
would like to be able to edit the template from the management interface.
The reason for using a ZopePageTemplateFile is to initially give a standard
ZPT, which can be modified if necessary.  Is the reason I cannot edit the
template, just undo changes, because it is not a ZopePageTemplate object?

product code:
self.var =ZopePageTemplateFile('zpt/index_html',globals())

ZMI code:
<a href ="var/manage_workspace">Var</a>

Maybe a Folder Object would be better?