I would suggest you setup (or use an existing) webservice for the PrinceXML end of things.
DocRaptor is a service that uses PrinceXML for HTML to PDF generation: https://docraptor.com/
Or you could setup a simple inside-the-firewall webservice (running on something that is not AIX) that takes in HTML and pipes it to PrinceXML, and spits back a finished PDF.
You may also want to look into getting the open-source wkhtmltopdf
(http://wkhtmltopdf.org/) to compile on AIX, if you need PDF generation, but not married to PrinceXML for doing so. (Though I cannot find anywhere in a cursory google search that has done it, so I'm not sure if it is possible).