Expires header data with htaccess?

Hello,

I am trying to optimize a website and with pingdom.com i get the Leverage browser caching grade of 0.

Now i thought i could set expires by editing .htaccess like so

<IfModule mod_expires.c>
    ExpiresActive on
    ExpiresByType text/css "access plus 2 months"
    ExpiresByType text/javascript "access plus 2 months"
    ExpiresByType image/ico "access plus 2 months"
    ExpiresByType image/jpg "access plus 2 months"
    ExpiresByType image/jpeg "access plus 2 months"
    ExpiresByType image/gif "access plus 2 months"
    ExpiresByType image/png "access plus 2 months"
    ExpiresByType text/css "access plus 2 months"
    ExpiresByType text/html "access plus 2 months"
</IfModule>

But still pingdom gives a grade of 0 and telling to set the expiredata. How can i do this?

regards