The SSLV Appliance shows the "Invalid Known Certificate with Key data: [csr'],['empty']" error when trying to import a certificate.
SSL Visibility needs both the private key as well as the certificate.
The PEM needs to include both the private key and the certificate information in the same file, not only the certificate.
It should look as follows:
-----BEGIN RSA PRIVATE KEY-----
-----END RSA PRIVATE KEY-----
The solution requires that you go into the device that you are trying to certify and generate the certificate and the private key, so then you can import both into the SSL Visibility appliance.