Assuming the task begins triggering immediately, runs indefinitely and executes a program:
DailyTrigger dt = new DailyTrigger();
dt.Repetition.Duration = TimeSpan.FromHours(23);
dt.Repetition.Interval = TimeSpan.FromHours(1);
new TaskService().AddTask(taskName, dt, new ExecAction("notepad.exe", "c:\\test.log", null));