When you create a recurring Appointment, you must set the date portion of the PatternStartTime and PatternEndTime properties.

If you set values for the AppointmentRecurrence object's PatternStartTime, Duration, and PatternEndTime properties, then your settings override the Appointment's associated settings.

When you set these three properties, — Outlook Mobile ignores the Duration setting and defines the Appointment with the PatternStartTime and PatternEndTime settings.

If you set any two of these properties and leave the third property undefined, — Outlook Mobile calculates the undefined setting from the two properties you set.