I see a lot of these complaints every spring, when the SL's come out of the garage for the first time in months.

It's actually pretty simple. R129 roof control modules (RST) don't like low voltage situations or jump-starts!!! There is almost certainly fault code 128 stored in the ECU. Sometimes this code can be cleared, other times not. As long as this code is present, operation of the top is blocked. You'll need to have a shop equipped with SDS clear all the codes and see what happens.