The PEM certificates created in Creating Client Certificates Used for Accessing the Repository will work to access the secured repository with the pkg client. However, to access the browser user interface (BUI), you must convert the certificate and key to a format that Firefox can import. Firefox accepts PKCS12 keystores.
Use the following OpenSSL command to create the PKCS12 keystore for Firefox:
$ openssl pkcs12 -export -in /path-to/certificate.pem \ -inkey /path-to/key.pem -out name.p12
To import the PKCS12 keystore that you just created, select the following Firefox menus, tabs, and buttons: Edit > Preferences > Advanced > Encryption > View certificates > Authorities > Import.
Import one certificate at a time.