Rendering Content MathML Dynamically

There is a long version and a short version of my question, so let me
start with the short version.  Why does the "MathML Tester" at
mozilla.org not work with Content MathML?

Here is the link to the tester:

http://www.mozilla.org/projects/mathml/demo/tester.html

Now for the longer version of the question.  I am working on a Java
applet with a public method which can return a snippet of Content
MathML to JavaScript.  I want to insert this snippet somewhere into
the (X)HTML and have it render dynamically.  The tester renders its
MathML  by writing it to the src attribue of an iframe.  This works
fine with Presentation MathML, but not with Content MathML.  I have
tried several other approaches, such as putting the Content MathML
into the inner HTML of a div element, or into the contents of a pop-up
window.  All of these approaches work fine with Presentation MathML
again, but not with Content MathML.  The problem seems to be that when
the JavaScript is handling the Content MathML, it can't pick up on the
mathml.xsl stylesheet that handles the Content to Presentation
mapping.  I have tried modifying the tester's code to be sure the data
which is being written to the iframe includes the stylesheet link.  I
have also tried forcing the XSLT to be applied using XSLTProcessor's
and such.  Nothing has worked.  I presume this must be a design
feature rather than a bug, but I'm not sure of that.  Am I missing a
workaround?  Am I just not using the XSLTProcessor's correctly?  How
can I get the mathml.xsl stylesheet to be applied to dynamically
rendered Content MathML?

(BTW:  yes, I am trying to do this in Firefox 2.0, Windows and/or
Linux.  And yes, for my purposes, it is important that I stay with
Content MathML.)

Regards,
[email protected]