I apologise in advance for creating another thread on this topic, I know there's dozens on the subject already, but I'm struggling to understand if I'm doing something wrong here or I'm hitting a limitation with the product(s).

We have a handful of users with Blackberry's who are currently using Google Apps for their mail and calendars. We can't get them to move to Zimbra until we solve the issue of calendar sync - they need to be able to view AND create appointments from their BB's.

As there's only a few users involved, we hit upon the idea of using Google Calendar as a "middle-man" - Blackberry syncs with Google, Zimbra syncs with Google, problem solved. However, I can't make this work: Zimbra's "public calendar" is view-only, so Google can't push changes down to Zimbra.

Adding the Google Calendar into Zimbra has the same issue: I can view the appointments in the Google Calendar fine, but I can seem to add appointments to the calendar. Creating a new appointment adds it to the "Zimbra" calendar, and dragging that appointment to the Google remote calendar makes the appointment disappear.

Without resorting to scripts that publish .ical files, or BES, does anyone have any insight into getting this working in as simple a fashion as possible?