Sets an alarm for the appointment specified by MessageID. This command fails if the item identified by MessageID is not an appointment or it the appointment is past.
AFTKN_ITEM_SET_ALARM or 655
VOID ItemSetAlarm(ANSISTRING MessageID; WORD HoursBefore; WORD MinutesBefore; [ANSISTRING ProgramToLaunch])
Unique item identifier, returned by ItemMessageIDFromView().
Hours before the appointment to sound the alarm.
Minutes before the appointment to source the alarm.
(Optional) Path and name of a program to launch when the alarm goes off.