Sit inside the car, lock it using the remote, and sneeze or jiggle about - that will set it off
In order to open locked doors and hatch, you must first disable the alarm.
You CAN open a locked door by using the key in the lock, however, you only have 20s or so (not sure if this is the correct interval, have not timed it) to disable the alarm by putting the key in the ignition.
I think you may need to put the key in the ignition as well as turn it to the first notch in order to diable the alarm using the key - this is what I do when I use the spare key which is not a remote key. Someone should check and verify if this is necessary