1996 C220 - changed doors. problem with key
 

1996 Mercedes C220

I just replaced the drivers door with one from a dismantler and got the key with it. The problem is the key turns in the lock but it does not activate the pneumatic locking system or the mechanical one that brings the door button down when turned.
I can lock the car using the trunk lock but all the new key/door does when the key is inserted into the lock is nothing. Once it opened the door but wouldn't lock it. Now it does nothing. still, when I lock it from the trunk, the lock goes down on the drivers door.

The body man that replaced the door for me informed me that it would be a very difficult thing to swap out the handle/lock assembly.

Any thoughts?