A couple of posters have stated and my owner's manual agrees that pressing the unlock button on the fob unlocks the rear hatch which seems to be pretty common behavior among various car brands (well, some brands require two unlock button presses). I haven't read a response from you about this. Have you tried pressing the unlock button on the fob to unlock the rear hatch? There is a setting in iDrive for the behavior of the unlock button, so maybe it's not set as you prefer. The button in the door jam shouldn't have to be pressed to open the rear hatch.