If the green key was inserted and downloaded the info to the new ignition switch, half the work is done. I assume if you put the black (original) key into the ignition switch the steering wheel unlocks, but you probably can't turn the key to start it. if you note the red LED on the key, it may be lit up. This means the ignition switch is downloading info from the black key. When the red LED goes out, the key should then turn to start, although the engine may not start. This is where the dealer may have to step in and program the engine computer. They are vehicle-specific. oh, come to think of it the dealer may also be required to get the new ignition switch to work anyways, there are electronic safeguards built into the system to keep theives from buying them and enabling the system. There is an (electronic) unlocking procedure that needs to get done before it'll work, possibly before it'll even allow the steering wheel to unlock.
The transmission computer will also need to be version coded to the car, as will what you call the "security computer" which MB calls the PSE pump.
I assume the green key is in the possesion of the dealership, the core charge on the green key is HUGE, they have to have that key back or it's mucho dinero for the dealer it was sent to. I assume the car isn't at the dealership or they'd have it all straightened out by now. If it isn't, you really need to get this car trucked to the dealer and get this baby straightened out. Anytime you start dealing with the EIS, engine control moduel, keys, etc, it's dealer time, MB won't and doesn't have to release info on the security sensitive features of the car.