After contacting Dell support with no resolution I contacted Avocent. Their response was:

You cannot replace the certificate on the actual KVM. You can only replace the certificate on the DSView3 management software if you have purchased the DSView3 software to manage the KVM.

"After contacting Dell support with no resolution I contacted Avocent. Their response was:

You cannot replace the certificate on the actual KVM. You can only replace the certificate on the DSView3 management software if you have purchased the DSView3 software to manage the KVM.
"

We're using a KVM 2162DS with one certificate that has been given out by our CA, just:

# cat kvm.domain.com.cert kvm.domain.key >> kvm.domain.com.pem

and upload into KVM 2162DS