The link was helpful. Here are the simple steps I will share for getting your 3rd-party cert working with the ClearOS 7 webconfig:


1. In the webconfig, navigate to Systems -> Settings -> Certificate Manager
2. Activate the local Certificate Authority by entering in the necessary information
3. Under the External Certificates section, click the "Add" button and upload the certificate, key, and intermediate file
4. Login to ClearOS via SSH