[maxihari]

+1

OK... So I have a 2010 135i. I was charging the battery in-place in the trunk with the negative battery cable disconnected. Closed the trunk lid and yup...couldn't get back in as the trunk latch is electric release.

Previous posts were correct, it's an easy solution, and a wise design by the BMW folks in lieu of a key latch or cable bypass.

I found this website : http://www.bavauto.com/ It has a complete list of beemers and the under hood electrical connections for this problem.
As posted, most of the Beemers have a positive electrical terminal in the engine compartment. In my 135i it's right behind the windshield washer fill reservoir, red-capped and marked as a "+" terminal.
Connect a set of jumper cables from a donor car to the terminal. (red to the terminal and black to a metal bracket in the engine compartment with good chassis ground connection)

You don't even have to start up the donor cars engine. Go back to the trunk and use the key fob button to open the trunk lid. Easy-cheesy.. Reconnected the negative battery terminal to the battery when the charge was complete. Car started right up and no reprogramming of anything required...

Cheers,

Mark (SF Bay Area)