3.1.4.1.3 Setting a Time Flag
The client sets the following properties to flag a Message object with a time flag.<16> Some of these properties cannot be set on a meeting-related object or a Task object. For details, see the property definitions in section 2.2.1.
PidTagFollowupIcon (section 2.2.1.2)
PidTagToDoItemFlags (section 2.2.1.6)
PidLidToDoOrdinalDate (section 2.2.1.13)—set only if it does not already exist on the object
PidLidToDoSubOrdinal (section 2.2.1.14)
PidLidToDoTitle (section 2.2.1.12)
PidLidFlagRequest (section 2.2.1.9)—set only if it does not already exist on the object
PidLidFlagString (section 2.2.1.10)—set only if it does not already exist on the object
PidLidValidFlagStringProof (section 2.2.1.11)—set only if it does not already exist on the object
PidTagFlagStatus (section 2.2.1.1)
PidTagReplyRequested (section 2.2.1.4)
PidTagResponseRequested (section 2.2.1.5)
PidLidTaskDueDate ([MS-OXOTASK] section 2.2.2.2.5)
PidLidTaskStartDate ([MS-OXOTASK] section 2.2.2.2.4)
PidLidCommonStart ([MS-OXCMSG] section 2.2.1.18)
PidLidCommonEnd ([MS-OXCMSG] section 2.2.1.19)
PidLidTaskComplete (section 2.2.2.2)
PidLidTaskStatus (section 2.2.2.1)
PidLidPercentComplete (section 2.2.2.3)
Even if the user does not specify dates for the PidLidTaskStartDate and the PidLidTaskDueDate properties, the flag is still considered a time flag if the PidTagToDoItemFlags property is set to todoTimeFlagged (0x00000001).