Request for unpublished document in the live site does not return a 404 status code

See HIP-510.

URL like http://www.demo.onehippo.com/products/food/2010/07/recycled-plastic-cups.html works, changing any letters in the last bit will return an empty document BUT with a 200 (OK) code, for example: http://www.demo.onehippo.com/products/food/2010/07/recycled-plastic-cupsBLABLADOESNOTEXIST.html

If a request is done for a URL that can be matched in the HST but has no document behind the matcher (/en/news/2011/02/this-document-does-not-exist.html) returns an empty page. This empty page also returns a 200 (OK) status code instead of 404 (Not found).
This can happen if someone follows a link on an external site to a page that has been published before but is now offline. Google does not remove the URL from its index because the status code is wrong.
Define in the HST components which beans are absolutely necessary to build up the page (i.e. the detail page main document). If that one is missing, handle this as an error page.

This seems to happen for all url's that can be matched to a component, but when the document can't be retrieved. Implementing a fix similar to that of HIP-510 should fix this.