I have the same problem. I'm trying to use this functionality to generate a pdf from a HTML page with a customized 'page2fo.xsl'. I need to customized the file only for my application because in the page there are some HTML tags that I don't want to display in pdf, like menu, header etc.
I saw the same article, and I don't know how can I modily the XSLTTransformer.
In my case I did some test with the rewriter packege below my own app packge. It's worked, but when I try to do the same configuration to another application, both use the same page2fo.xsl. In that case, the instance use the file with the higher priority (order property).