Hot to prevent copy/paste of items in public folder

[awjenning]

We have an application that uses Exchange public folders. I need to
prevent users from using copy/paste (edit|copy, edit|paste, ctrl+c,
ctrl+v) on the messages in these folders. They are doing this from the
folder view. We a custom form associated with each of these folders.
There is code the form which prevents in-cell editting by detecting
when an item_write event fires when there was no previous item_read
event. Unfortunately these form events do not fire when users
copy/paste items. Is there any way to prevent the copy/paste?
Thanks,
Tony