1999 Mercedes Benz 430e REPLACE FUEL SENDING UNIT

I PURCHASED A NEW FUEL SENDING UNIT. IT SEEMS SIMPLE TO REPLACE BUT HOW I CAN GET TO IT. CAN IT BE REACHED FROM THE TRUNK OR BY REMOVING THE REAR SEAT BACK? DOES THE REAR SEAT BACK PULL OUT? REMOVE THE REAR SEAT CUSHION FIRST? THANKS.