Certificate install via AD

I have a new Content filter I am installing on my network. In order for the content filter to filter https SSL traffic, I need to install a certificate to each computer. I would like to add this certificate to my AD instead if possible. I do have a Windows Server 2003 certificate authority in my network, but I am unsure how I would go about adding it.

My choices for downloading the certificate from the Content filter are a PKCS#12 which requires I create an export password, and a PEM certificate which is downloaded and exported from Mozilla as a .CRT X.509 certificate.

I am looking for directions on how I can allow all of my workstations in AD to trust this certificate without manually installing it to each workstation.

Once the certificate is trusted, I am assuming users will be able to browse through the content filter and see the SSL web sites they are trying to reach without getting the error message that the sites certificate cannot be trusted.

Thanks in advance