I'm attempting to redirect just one URL inside a .htaccess file with Redirect:

Redirect 301 /index2.php?option=com_rss&feed=RSS2.0&no_html=1 /something/somethingelse/

I've got a couple of other similar rules which work using directory structure Web addresses, but that one will not get processed.

Redirect 301 /old/url/ /new/url/

Must i do anything whatsoever special?

Thanks!

With [cde] you are able to only test for URL paths, or even more particularly, URL path prefixes although not for that URL query. But that can be done with mod_rewrite:

Redirect