New answers tagged outlook
You can do this by turning on incoming email in your SharePoint calendar settings. If you email the event to the email address as an invitee, then any time you send out an update, that update will be reflected on the SharePoint calendar.
To debug the issue I would use Fiddler to see the requests sent to and the response received from SharePoint. You should see a request invoking the UpdateListItems web service, as described in this post.
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