Configuring SSI under Apache 2.0 and RedHat 7.3

[XanderMahony]

I am running RedHat 7.3, Apache 2.0, PHP 4.3.8.

I have editted httpd.conf to the following:

<Directory />
Options Indexes FollowSymLinks Includes
AllowOverride All
AddType 'text/html; charset=ISO-8859-1' htm
AddType text/html php
AddHandler server-parsed php
</Directory>

and added the line:

<!--#include virtual="test.ssi" -->

into test.php inside my htdocs directory. Everything other than SSI is configured, Apache is working fine, PHP is working fine, etc., but when I go to [localhost...] the include doesn't include anything, the line:

<!--#include virtual="test.ssi" -->

is just in the page source without any change. How come Apache doesn't include test.ssi into the code?