A solution I have found that works well uses the Sling 404 handler to
fake PIE.htc. First, follow these instructions to set up PIE.htc in CQ:
https://gist.github.com/msulliva/5971565. Second, create a Sling 404
handler, using instructions found here:
http://dev.day.com/docs/en/cq/current/developing/customizing_error_handler_pages.html.
Third, ensure your css behavior() points to just "PIE.htc" (not
required, just recommended). Finally, at the top of the 404 handler put:
if (request.getRequestURI...