Hi you guys,
I put the following code in the 404.php of my theme:
<?php wp_redirect( "http://www.myredirecturl.com", 404 ); exit;
WordPress returns a white screen in this case.
If I use another status code like 301 or 302, the problem doesn't exist.
I'm aware that I can define ErrorDocuments in my .htaccess, but would like to let my WordPress multisite installation handle this itself.
(Btw: I also tried this with a WP single blog installation – same problem here)