IE7/8 and certificates

Hello

I am an administrator of few websites with self issues/made
certificates/SSL(openssl) generated in linux.
When I access my websites with IE7 or IE8 I get a warning telling me
that certificate could not be confirmed
(which I am aware coz they cant be confirmed by other trusted org on
web) and asks me if I wanna go ahead and visit that site.

I wanted get rid of that stupid warning so I added my site to trusted
site and installed websites certificate to Trusted root publishers
inside IE, but none of that helped.I still receive warning error.

Is there a way to add certificate to IE so that this error/warning can
be avoided ?

Thanks