Yesterday, I corrected a little bug I discovered. When an appointment had several attendees, my program would create multiple entries in Outlook, each with one attendee. I moved a line of code and now things work like they should.
What I want to achieve, is marking the appointments in a non-default color, which you can do in Outlook manually in the New->Appointment dialog. By default Outlook chooses None, but you have Important, Personal, Holiday, etc. The odd thing is, that the “label” (as it is called in the dialog) is not an exposed property of the AppointmentItem you can set.
You need to access Outlook via de MAPI-interface, look for the Calendar-folder, find the item in the Calendar folder, and then change some properties. Very odd, and not very well documented. I spend a great deal of the evening looking for samples how to do it, but so far I have no working code.