Replacing main site feed with recent global posts feed

Dear friends,

I wonder how to replace main WPMU site feed with Recent global post feed by using Recent Global Posts Feed Plugin?

when I added .htaccess rule like this (look at 'feed/'):
RewriteRule ^(.*/)?feed/(.*) wp-content/recent-global-posts-feed.php [L]

it remains showing my main site feed, not the recent global posts feed.

Please help me

Thanks in advance,

Kai