C'mon, bsf and javascript extensions to xslt have nothing to do with FOP,
pdf and afaiu original question. Correct me if I'm wrong, but I believe
pdf 1.4 supports scripting, so it's possible to produce such pdf file,
which will run some script on user click.
With Adobe Acrobat it is possible to add Adobe jscripting to PDF files.
After researching a bit I found (correct me if i'm wrong) it is not possible
to use external COM/OLE objects from Acrobat JScript like it is in HTML/IE.
Only the internal Reader/Plugin objects: doc, search, fullscreen, bookmark
...
//matts
XSL-List info and archive: http://www.mulberrytech.com/xsl/xsl-list