C# - Problem Sending Meeting Updates with CDO

[Christie]

I am having a hard time sending meeting updates to attendees. I can
get the updated meeting to save to the organizer's calendar, but then
when I send it the meeting is sent to the attendee as a new meeting
instead of an update (It seems that Exchange assigns a new UID when
the Save method is called, so the attendees' calendar can't link it
with the original UID?!). If I try to send without saving first, the
old meeting is sent instead of the update.

Here is a sample of the code:

string sURL = "http://localhost/Exchange/" + username + "/calendar";

ADODB.Connectio n oCn = new ADODB.Connectio n();
oCn.Provider = "exoledb.dataso urce";

oCn.Open(sURL, username, password, 0);

CDO.Appointment oApp = new CDO.Appointment ();
//Set updated Fields
oApp = ConvertVEItoCDO Appointment(app t, oCn, username, password, sURL, false);

//Get URL location of oApp
string UID = oApp.Fields["urn:schemas:ca lendar:uid"].Value.ToString ();
string href = GetExistingAppo intmentHrefFrom UID(UID, oCn, username);

oApp.DataSource .Open(href, oCn,
ADODB.ConnectMo deEnum.adModeRe adWrite,
ADODB.RecordCre ateOptionsEnum. adFailIfNotExis ts,
ADODB.RecordOpe nOptionsEnum.ad OpenSource,
username, password);

oApp.DataSource .SaveTo(href, oCn,
ADODB.ConnectMo deEnum.adModeRe adWrite,
ADODB.RecordCre ateOptionsEnum. adCreateOverwri te,
ADODB.RecordOpe nOptionsEnum.ad OpenSource,
username, password);

CDO.ICalendarMe ssage iCalMsg = (CDO.ICalendarM essage)oApp.Cre ateRequest();
iCalMsg.Message .Send();

Any help would be greatly appreciated!