Scriptalias as /rt with apache + fastcgi

Hi, I am using rt 3.4.4 on RHEL 4 with fastcgi, and I am suprised that
it will not work when I change the scriptalias to /rt instead of / Is
there something else that has to be changed besides the scriptalias in
apache and $WebPath in ? All it does is let me login,
andthen displays the page:

You haven’t yet configured your webserver to run RT. You appear to have
installed RT’s web interface correctly, but haven’t yet configured your
web server to “run” the RT server which powers the web interface. The
next step is to edit your webserver’s configuration file to instruct it
to use RT’s mod_perl, fastcgi or speedycgi handler.