As I understand it, Attention Alerts need to be sent to PSO via an external system. Within a dsScheduleData message include the following along with an input_reference:

"Schedule_Event": {
        "id": "TEST35-A", 
        "date_time_stamp": "{{current_dttm}}", 
        "event_type_id": "AO", 
        "event_date_time": "{{current_dttm}}", 
        "resource_id": "1000"
    }