cfexchangecalendar modify action : cannot remove a requiredAttendee

Hi,

are there any known issues about changing required attendess of an event using the cfexchangecalendar tag with action modify (CF10, Exchange Server Version 2010)? It is possible to add another attendee, but if I want to remove an attendee the changes don't take effect.

Example:

Old list of attendess a@mail.com,b@mail.com, c@mail.com, strored in the associated exchange event item.

<cfset eventStruct.requiredAttendees = "a@mail.com,b@mail.com">

<cfexchangecalendar

    action = "modify"

    event = "#eventStruct#"

    uid = "myEventsUID"

    connection = "establishedConnection">

Thanks in advance