@Maciej-Kulawik
I found it as 'Scene' switch but this example send only V_SCENE_ON the first time (the switch is still ON later)

I added 2 lines and works perfect with Domoticz:

MyMessage scene(KEYPAD_CHILD_ID, V_SCENE_ON);
MyMessage scene2(KEYPAD_CHILD_ID, V_SCENE_OFF); //added line

gw.send(scene.set(keyInt));
gw.send(scene2.set(keyInt)); //added line