I have a .htaccess file that says:
ErrorDocument 403 /404test.php
ErrorDocument 404 /404test.php
and I have a PHP file (404test.php) that says:
header("HTTP/1.0 200 OK", true, 200);
print "all done!\n";
Obviously, this isn't going to output anything useful, but I would expect the output to be delivered with a HTTP 200 status code. But instead, it has a 404 code which I don't seem to be able to override.
BTW - this has worked on my own Apache/PHP installation running on Ubuntu. So I'm guessing this might be something to do with the way DH manage their servers?