phranque - 6:50 am on Jun 11, 2011 (gmt 0)

In my case I always get a server response 403 instead.

403 should be the response you get when you request a directory in which no DirectoryIndex has been specified or the default directory index document does not exist and "Options Indexes" has not been specified.

403 actually means Forbidden:
http://www.w3.org/Protocols/rfc2616/rfc2616-sec10.html#sec10.4.4 [w3.org]

i assume that's what you mean by "access denied".

i would also assume that the xml document you are getting in response to your "Forbidden" request is a custom ErrorDocument:
http://httpd.apache.org/docs/2.0/mod/core.html#errordocument [httpd.apache.org]