Converting an OpenSSL CA

You can convert a PEM-style Root CA key to a PKCS12 file that can be imported in EJBCA.

openssl pkcs12 -export -out server1.p12 -inkey cakey.pem -in ca.pem -name privateKey

You can import the CA with the Admin GUI or the CLI. See the section 'Export and import CAs'. 
After importing CAs you can also import users and certificates. See the section 'Import users'.