If you turn on the lamp with the switch, unfortunately it will not go off by itself anymore. You give the switch parallel to the detector's relay contacts, i.e. two wires (except for blue).
Since you can (as you wrote) connect the lamp itself to the detector, then just connect these two wires from the switch to the detector, or more precisely to the phase input and phase output to the lamp.
In other words, you connect (in your photo) 3 blue, 1N, 2N and 3N cables.
Blue from the 4N circuit breaker you give to this unsigned from the detector (on the left side) and there you connect 1L with the lamp.
Then you connect 3L with 2L and there the other end of the switch or 4L.
The cable 111 gives you an indescribable cable with a plug (protective).
Ps. The detector's terminals can not be seen, but I suppose that when looking from the left to the wires, the first one is the phase output to the lamp, the second to the phase supply, the third one is neutral (0). This is important information that no one should ever attach this vein to protection.
By the way, such a small note that this cable from which the power supply for the lamp comes out should have a shirt, eg red, if you used a cable such as in the picture.
