Meeting request message after appointment is updated shows UTC time

I'm using Exchange 2010 EWS Managed API to create and update appointments. When appointment is created, in the meeting request, it shows:

When: Wednesday, March 16, 2011 4:30 PM-4:45 PM. (GMT-05:00) Eastern Time (US & Canada)

Then I update the meeting, not necessarily the meeting time, but when I do an update with the following code:

meeting = Appointment.Bind(service,newItemId(ItemID));

meeting.Update(ConflictResolutionMode.AlwaysOverwrite,SendInvitationsOrCancellationsMode.SendOnlyToAll);

When I open the meeting request in Outlook 2010, I get this:

When: Wednesday, March 16, 2011 8:30 PM-8:45 PM. UTC

Same exact meeting, if I open the request in Outlook 2007, this line does not show up at all, which is what I want.

I have other parts of the meeting request that do reference the time in local (Eastern) time zone. But this part showing in UTC is really confusing to the attendees. I don't think I can control the "When" part of the message. I've tried setting starttimezone, specifying time zone when connecting to Exchange service, but nothing made any difference. Is there anyway I can either make an updated meeting show the same text for "When" as the initial request (local time referencing GMT), or at least suppress the line that shows UTC time?

Thank you in advance for any input.