[tedchs]

That was not my experience. I had the same problem, and their support would not let me change to a different client cert.

[lambada]

I've done that several times in the past, never had to contact support. Just go through as a new user. It means you have to revalidate your domain ownership but that's not much of a hassle.

[_nalply]

I even used a numbering scheme: [e-mail] [e-mail] and so on.