hello there 'turbochick', not sure what your doing wrong, my mk4 gti dosnt have a release button only for the fuel flap, the remote locking set up should be as follows, press once(unlock) will un lock the drivers door only!, press (unlock) twice and the boot and passenger doors etc should all open!!, give that a go and see how you get on!! ive never had to use the key on mine!!!

welcome to the forum!!