Originally Posted by mattslight
The issue does not occur when using Outlook 2007/2003 or OWA to accept the calendar invite. I can only assume that Entourage is deleting the calendar invite in a different way, not recognized by BES.
This is because the Outlook client connects to MS Exchange using native protocol. OWA is native to MS Exchange. Entourage connects to Exchange using MAPI.
MAC OS 10.6 is suppose to have bult-in support for MS Exchange 2007. I have not tested this but I would guess you have to use the bult-in mail client.