I have created a new blank calendar "Conf"within my account's Calendar folder. I have granted Publishing Editor permissions to several coworkers and sent them Sharing Invitations. They have opened the calendar and made appointments within it. I can see these and things are working as expected through the Outlook 2010 UI.
In VBA, I can get a successfully set reference to this calendar that I have shared as an Outlook.MAPIFolder object and its contents as a collection of Outlook.AppointmentItem :
Dim objConf As Outlook.MapiFolder
Dim objAppt As Outlook.AppointmentItem
Dim i As Integer
Set objConf = Outlook.Session.Folders("myAccout@xyz.com").Folders("Calendar").Folders("Conf")
For i = 1 to objConf.Items.Count
Set objAppt = objConf.Items(i)
Debug.Print i, objAppt.Subject, objAppt.Start, objAppt.Organizer
However, the Organizer property always contains my name (seemingly because it is located within a subfolder of my calendar) rather than the person who created the appointment or last modified it.
In the UI, I can determine the last modifier by opening the appointment and looking at the right-bottom corner (in this example, my coworker, J. S.):
What property of the AppointmentItem would reveal this name?