My permalink structure is /archives/%year%/%monthnum%/%day%/%postname%/. The directory /archives exists and contains some non-WordPress PHP pages (with .html extensions). The .htaccess file for this directory consists of the line "DirectoryIndex index.html".
When I go to http://www.mydomain.com/archives/, the file index.html loads as intended. But in my server logs it is recorded as a 404 error. (The LiveHTTPHeaders Firefox extension also says that the page is a 404.) If I go directly to http://www.mydomain.com/archives/index.html, the page also loads, but the HTTP status code returned is 200 OK.
I want to be able to go to http://www.mydomain.com/archives/ and have index.html load with the proper HTTP code. I tried using the PHP header() function to replace the original Response header with a new one, but my server logs are still showing 404s, so that doesn't work.