(Untested idea) I'd suggest creating your own Root CA with an expire-date far in the future. Install it's public key as a trusted certificate and all derived certificates should not prompt any issues anymore
Then I thought, WTF am I doing?. I realized that I was making computers that would circumvent the world's security apparatus. Of course it won't hurt if I make no errors of practice or judgement but, am I really smart enough to handle highly radioactive material.
I ripped it all out. It makes me shudder thinking about it.
This becomes a nightmare, when the original admin in the org is gone long times ago.