iCal questions about GW2012 appointments

Some things I noticed while sending appointments to external email systems (GW2012SP1 clients+domain+gwia sending to MS Exchange 2010 with Outlook 2010 clients):

- Sending an appointment to external users is OK (iCal message, can be accepted etc.). But when changing something minor in the appointment (extra recipients, location) results in 2 iCal messages in the mailbox of the external user: one cancellation and one accept-mail. No change notification. Is this a defect? Because the UUID of the iCal message is the same. So there should be a change notification instead of a cancel+accept notification (!?). Or is there a setting to change this behavior?

- Cancelling an appointment with the option 'remove this item from other recipients mailboxes' without any further comment never sends an external iCal message and thus the appointment stays in the external mailbox. Cancelling an appointment with a text in the comment field sends an iCal message to external recipients for the cancellation and the appointment is removed from the external mailbox. This seems to be a bug.

Thanks in advance,
Jan.