How does Entourage reference Calendar Events from Calendar Email Messages

[quico.gonzalez]

I work in an Exchange evironment and I am trying to write an
applescript that allows me to find the original calendar request of a
selected calendar event. There seems to be no way to uniquely identify
the email calendar request to the selected calendar event. There
obviously must be something in the message otherwise a meeting
organizer would not be able to send updates to an existing calendar
event.

The reason for this is Entourage does not allow you to change your
attendee status from within calendar event, you must track down the
original email request, for example if you want to decline a previous
accepted meeting. I am trying to simplify this process with an
applescript.

There is a GUID within a calendar event that seems should match the
UID that is available in the original email request's source. I have
noticed they do match up for calendar events I create compared to the
source of the email attendee responses, but not calendar events that I
am invited to, which are the only ones I care about. I could make
assumptions, such as matching up the subjects, assuming there is only
one event with the same subject, but I would like my script to be a
little more robust. Any ideas? Let me know if you need more
information.