[Zope] Zope pdf's on the fly

Microsoft's IE uses non-standard techniques to determine the type of a file. To bend it to our will, we've found that the generation program needs to be named with a '.pdf' extension. This, of course, makes it a bit difficult to embed in a dtml call. (As a form action, it works...) What I have is an external method that manages the interfact to HTMLDOC by building a html file, sending it to HTMLDOC, gathering the result, and returning it with appropriate headers to the client. If I use a form to set up parameters to the external method and <form action="doit.pdf()"> .. </form> it works fine. Of course, <dtml-varB expr="doit.pdf()"> doesn't.