Hi, I have 2 dogs that travel in the back and had the same problem.
The way to do it is...
Take the key out.....
Standing outside the car with the drivers door open (has to be the drivers door)
hold the inside door handle open, and flick the drivers door lock switch (you'll hear an audible click as the other locks around the car 'lock')
when you close the door you will see the indicators flash 3 times and the doors will all be locked with the internal sensors deactivated.
Hope this helps !

