EDIT, another thought, did the blade break off or did the super small roll pin come out and blade fell out of fob?

You have the single button, IR, flip key correct? Complete housings are sold on e bay for $ 12 but you would have to get the key cut.

You can get a "flat key" for about $ 40 from the dealer , this looks like a regular key with a short head and it has the RFID chip to work the DAS. This will start the car without programming as MB has a list of keys / slots the car has in play. ( If someone used aftermarket SW to program a key, MB won't know this unless a scan tool is hooked up )

Your system is supposed to be the same as my 97 cars except the DAS function is inside the AAM. A coded signal from DAS to ECU is sent over the CAN bus so this isn't a simple power up to bypass.

The only programming would be for remote locks or to delete the fob you are no longer going to use. On my 97 programming the remote consists of pressing the button twice and starting the car.