p.s. someone suggested i could do this easier (part 2 of the question) by using directly the remote control of the door and wiring the camera via the relay to the remote directly which works with a small 12v battery. In a few words glue the button of the remote permanently down and the camera...
here is the manual http://www.axis.com/en/files/manuals/um_p1355_49956_en_1303.pdf
see page 61
Notes: i have seen this thread https://www.physicsforums.com/threads/axis-camera-with-i-o-and-relay-to-turn-on-lights.538043/ but this camera is a bit different i think as it has digital inputs and...