better check with yoru dealer, a hard anchor point may or may not exist.
I would suggest you check with a MB dealer. There may be a built-in ahchor point under the parcel shelf for ready installation but again it may not exist. Such was not a requirement for cars sold in US until may be '99.
I found this out when I tried to have the anchor loop installed on our '97 e320. Dealer checked twice and told me there is no factory approved hard point for installation on the US market car. Apparently the metal sheet under the parcel shelf lacks a reinforcing member.
Not trying to discourage you from finding other possible installation method but I doubt any shop would want to tackle it for liaibility concern.
Hope you'll find a solution to this problem.