IIS 5, blocking an IP range, and custom errors

[Cervantes]

Hi;
I'm blocking my website to a certain IP range.

I went into my mmc console, the site, properties, Directory Security, specified the range with the correct subnet, tested it out, all was well, I got a 403.6 error trying to access it from one of the IPs in question.

I needed a custom error page, so I went in, made one, went into "Custom Errors", assigned it to 403.6. Had some problems getting the background image and embedded image to display, and in the process of fiddling with the webpage, temporarily removed the IP range.

So, I think I've got the firewall page working, I go in, re-add the IP range the same way I did before... except now, it's not showing 403.6 error... it's showing a straight 403.

So, I offer the ever-popular multiple choice question:

1) How do I make it kick back 403.6 instead of 403 errors?
or
2) How do I edit the 403 error document?

I've restarted IIS and checked all my settings and undone everything I did, and it's still coming up 403 with the default 403 page.
Any ideas?

Thanks,
Cerv