In order to secure a few virtual hosts on our intranet server, I have been requested to force user certificates authentication using our private CAs. One CA for each virtual hosted site.

Other than manual editing the apache site configuration files, is there a way to configure it using Webmin tools? I spotted a dropdown under Webmin's apache's SSL options page labeled 'Client SSL certificate'. There are a few options here and I am assuming the CAs need to attached/installed somewhere to appear in the selection list.

I tried multiple Google searches only to be flooded with ads and how to secure Webmin. Feel free to point me at a document.

Any help would be great.