mod_rewrite and IE

ive got a problem specifically with mod_rewrite and internet explorer

we dont want people accessing files by links from other websites so we
have the following setup in .htaccess:

RewriteEngine On
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://ourwebsite.com/
RewriteRule ^.*$ http://ourwebsite.com/index.html [L]

everything works fine when you click on the link from our website.com

the problem comes in when you right click and select save target as
in firefox it works fine.. but in internet explorer it doesnt work it
redirects and you get to download a copy of index.html

ive tried going around this by changing the .htaccess to the following:

RewriteEngine On
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://forum.gruwelijk.com/
RewriteCond %{HTTP_USER_AGENT} !^Mozilla/4(.*)MSIE
RewriteRule ^.*$ http://forum.gruwelijk.com/index.php [L]

it still doesnt work.. any ideas?

thanks in advance for your help :)