ColdFusion 10, IIS 7.5, and custom 404 page

I am attempting to setup a custom 404 error with CF10 and IIS 7.5. Previous to CF10 (and IIS 7), you can get the URL of the non-existent page via the querystring (e.g., 404;http://www.example.com/some/file.html) when the custom 404 page is processed. However, with CF10 and IIS 7.5, the querystring returns 404;http://www.example.com/jakarta/isapi_redirect.dll. Is there a way to retrieve the actual URL of the missing path, like in prior versions?