Dave Dash has posted about a method he developed, using a custom prepend file, to correctly obtain the PATH_INFO information for his server.

symfony and other applications rely on the server's PATH_INFO being set properly. Unfortunately, I use a nonstandard server that doesn't natively support CGI [...] but I can't figure out how to do a urldecode in my configuration.

To get around the issue, he created a file he prepended to each request (via auto_prepend_file) that took the value and urldecoded it to put it in another $_SERVER value.