[TYPO3-english] correct 404 handling

[Matyi Gábor]

Hi!

Could anybody tell me, how to configure the 404 handling in typo3 properly?

I installed the error_404_handling extension, and I created a 404 page.
(not visible, name is 404).
I configured the redirection to the page 404, and the
[FE][pageNotFound_handling] = /404 in the install tool as it is written
in this two page.

http://typo3.org/documentation/document-library/extension-manuals/error_404_handling/0.1.1/view/1/2/
http://typo3.org/development/articles/improved-404-handling/page/2/

If I open a non existent page, the 404 page appears with my content, but
  the html header is 200 or 301 and not 404.

What I configured wrong? Perhaps the realurl?

Gabor Matyi