I am using XML/SOAP (not the managed API) to create calendar events in Office 365. For attendees, I need to set the status (accepted, declined, etc.). In the other direction, I can read this property in ResponseType. From what I gather, this is read-only, and I cannot set it, even though when I do, I get no error from Exchange - it is just ignored:
<t:Attendee><t:Mailbox><t:Name>John Smith</t:Name><t:EmailAddress>john.smith@domain.com</t:EmailAddress></t:Mailbox><t:ResponseType>Accept</t:ResponseType></t:Attendee>
Am I correct that there is no way that I can set this property? How about using extended MAPI properties? When I tried using "ExtendedProperty" inside the Attendee, I got a schema violation. Can you show me how I can do this?