Raparicio, if you add a box(or w/e) to the components of a BP, in the details section, you can scroll down and see “add event” next to a little +. if you click the add event, a list of events that can be added to the event graph will open up. click the event you want to add and it will automatically be added to the event graph. this is really the only way that such events can be added to the graph, as they are not available from right clicking, or dragging off from a node referencing the box.