PATH_INFO empty, ORIG_PATH_INFO correct

Hello, I'm using PHP as CGI (not through Apache-action, but she-bang line containing the path to php). When I'm calling http://test.com/phpinfo.php/a/variable/url PATH_INFO should contain "/a/variable/url". I checked this with a perl-script, which printed out all environment variables and so I know that PATH_INFO was set correctly bei Apache. But PHP seems to perform some unwanted action, so that PATH_INFO shows "no value" and ORIG_PATH_INFO is correct. But this ORIG_PATH_INFO is not known by any script. How can I tell PHP not to touch PATH_INFO but leave it as Apache set it? Regards Marten