Redirect to 404 or 403? When you set the 404/403 error pages to nodes with a path, how then can you have Drupal go to the 404 path or 403 path instead of outputting the message on the page?

For example, if I type in www.mydomain.com/skdjhfjsdhfjsh, it shows the custom 404 text from my node. But, is there a way to make Drupal send the user to www.mydomain.com/404, so I can use Contexts/Blocks with in the content area of this specific page?
I agree that redirecting a 404 page is a bad idea.  One way customize error pages is the blocks404 module.