Show reminder for scheduler appointments in past

I am programatically adding two appointments to a rad scheduler, one with start DateTime in past and one with start DateTime on current date. The reminder only shows the appointment on current date. I also want to reminders for all appointments in the past as well. How can I achieve this.

The business scenario is when a user starts the application it should remind them of all appointments in the past from now immediately and the appointments on today 15 minutes before start.

Code below

Appointment appointment1 = new Appointment(DateTime.Now.AddMinutes(15).AddSeconds(5), new TimeSpan(1, 0, 0));
appointment1.Summary = "Appointment Today";
appointment1.Description = "Appointment Details";
appointment1.Reminder = new TimeSpan(0, 15, 0);
radScheduler1.Appointments.Add(appointment1);

Appointment appointment2 = new Appointment(DateTime.Now.AddDays(-1), new TimeSpan(1, 0, 0));
appointment2.Summary = "Appointment 1 day in past";
appointment2.Description = "Appointment Details";
appointment2.Reminder = new TimeSpan(0, 15, 0);
radScheduler1.Appointments.Add(appointment2);

radSchedulerReminder1.StartReminder();