Within Outlook 2013, if you want to add a custom flag to an item you get this dialog:
I am trying to figure out how to open this dialog using VBA? I can either open it for a selected e-mail item or if there is a way to open it directly and retrieve the date/data the user selected.
You can simulate pressing buttons with ExecuteMso
Private Sub AddReminderDialog_ExecuteMso()
Dim objItem As Object
On Error Resume Next
Set objItem = ActiveInspector.currentItem
On Error GoTo 0
If Err <> 0 Then
ActiveInspector.CommandBars.ExecuteMso ("AddReminder")
Else
ActiveExplorer.CommandBars.ExecuteMso ("AddReminder")
End If
End Sub
You can see the "AddReminder" when you hover over the button when adding to the Quick Access Toolbar or a ribbon.