ooh, that is a good question. I was thinking the key blade when reading your thread, but you've already mentioned this. Have you called Mercedes or Roadside Service for a work around? Because, I don't know what to tell you at this point. Have to tried unlocking the trunk with the keyblade, then releasing the seat backs and climbing through?

It's worth a shoot, that way, you could pop the hood, I can't remember if the E55 battery is in the trunk like my E63 or under the hood?

So go try it and let me know what happens?