XML to XML via XSLT, and then CSS?

Hi all,

It's possible to use XSLT to transform an XML document into HTML and
then style the HTML using an external CSS style sheet by way of the
HTML <link> tag, which the XSLT style sheet includes in the result
tree.

This works because browsers treat the <link> tag in a special way.

But what if transformation is not into HTML?

A processing instruction such as 

  <?xml-stylesheet href="css-sheet.css" type="text/css" ?>

is sufficient to display an XML document using an XML enabled browser,
but what if I what to transform the original XML document into a new
XML document (using XSLT) and then have the browser style it using
CSS?

The original XML document needs a new processing instruction:

  <?xml-stylesheet href="xslt-sheet.xsl" type="text/xsl" ?>

and the XSLT style sheet then needs to include a processing
instruction in the result tree that links to the CSS style sheet.

In short my question is this:

How do you pass processing instructions to a result tree, so that I can
point my XML enabled browser at an XML document, have it transformed
into another XML document using XSLT, and then have it styled using
CSS?

sdt