SSL is a standard secure communication protocol of the internet, it is not lavabits design and it is impossible for Lavabit to modify while still keep interoperability.
You do not seem understand the underlying problem, as many people are misinformed as to which key the government was requesting., They WERE NOT asking for the key of the private inbox data, they were asking for the GoDaddy Signed SSL key that encrypts the web browser session from the Lavabit User to the Lavabit server, not the user level key for the encrypted mail box stored on LB servers
This is the same protocol that HN uses for this very site, Amazon, Gmail, and thousands of other sites use every day to secure communications between public servers and the users of those servers