All US 140 cars had an infrared remote (switch blade) you can get one of those, with key from your dealer for approximately $150, you can also order just plain keys for about $15 the cars shipped wit two keys, two remotes, and a valet key. The new MB rules are demanding positive ID and a signature. My dealership made me give them a copy of my license, even tho I purchased the car there and had it in for service. They usually shipped are overnight depending where you live. I would not have a locksmith do it since they are more expensive and use brass keys not steel which is factory.
There is no way of getting into the trunk, since the gas tank is there, and getting the seat back out is a chore. If you really want to get into the trunk you coud realease it by finding the line going from the pump and putting a little pressure on it (like from a bike pump) pressure to unlock /vacuum to lock. Wait for the key!