They specifically tell you that you need to back up your login-cert or you
will lose access.
One year passed, and I checked my backups. Yup, there it was.
If you take security seriously, you should actually read what's on the page instead of clicking "next, next, next" like some driveby malware-installing Windows-installer. And then this shouldn't be an issue.
I guess this is StartSSL's way of not having to deal with people who don't take security as seriously as they do.