cfml

IIS question.
For lockdown, I've configured some URL patterns to be denied in Request Filtering, and configured a 404.5 Error Page pointing to a local URL on the site, but it still shows this generic but overly specific error message:
```HTTP Error 404.5 - Not Found
The request filtering module is configured to deny the URL sequence.```
That comes from the 404-5.htm file in the error pages location.
Can I not override that error page for some reason?

Turns out that the Request Filtering detailed specs inherit from higher levels, the the Feature Settings there don't. Sorted.