added:

From wiki Wed Feb 20 03:08:16 +1100 2008
From: wiki
Date: Wed, 20 Feb 2008 03:08:16 +1100
Subject: 1st RewriteRule?
Message-ID: <20080220030816+1100@www.mechanicalcat.net>

I don't understand the sense of the 1st RewriteRule in the last example (Roundup server)::

 RewriteRule ^/([0-9]+)$ http://mydomain.maindomain/sf/$1 [R,L]

And the <Directory> section is needed here as well (if the AliasMatch is used), I suppose...