Disable outlook "propose new time" button by iCalendar vEvent

I have a specific question. I sent out iCalendar files by the library iCal4j but now I need that the receiver of the iCalendar can't propose a new time. So the button 'propose new time' nee te bo disabled.

When I sent out a meeting request from 2010 and disable the option 'Allow New Time Proposals' then the property X-MICROSOFT-DISALLOW-COUNTER is set to true. This option seems to work with outlook 2010 but isn't accept by outlook 2007.

Does someone have an idea for a other property setting?

iCal4j code:

//add property so ms outlook knows that the users can't propose a new time
XPr开发者_如何学编程operty xprop = new XProperty("X-MICROSOFT-DISALLOW-COUNTER","TRUE");
vEvent.getProperties().add(xprop);

Edit It seems that outlook 2007 also use X-MICROSOFT-DISALLOW-COUNTER:TRUE to disable the button, but unfortunately this isn't accepted on the client's exchange server.

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Searching the iCalendar RFC, I did not find anything about disabling the option to reschedule an event; that seems sensible - any recipient could override a "no reschedule" marker by issuing a new event, so the users are going to have to abide by some social contract regardless.

Your Outlook 2010 solution clearly relies on something internal to MS Outlook, and which I doubt would be respected by any other program that uses the iCalendar format.

Relative to disabling reschedule for Outlook 2007 only, I did not see anything in a cursory search. If you have access to 2007, why not try the same technique you used to look at the 2010 events?