Obes,
I'm going to qualify this by saying I'm not at all an expert. We outsource all of our email to a service provider in town, and they handle all of this stuff for us.
That being said. ActiveSync is a proprietary MS mailbox exchange protocol. As far as I know it's only supported on Windows Mobile Devices and the iPhone. I know it's not supported by my Blackberry Bold..
How are you currently trying to connect the blackberry to exchange. I was under the impression that in order to get full mail, calendar, notes integration (via push) it required a blackberry enterprise server (BES) installation. This software allows the administration of all the devices in the enterprise as well as security policies. When I got my blackberry, i was given an activation address (BES Server) and a pin number. I entered those two items a long with my email address and the email account was added to my device and the security policies installed on the phone. Can you talk to your email admins?
That's the only method I know of connecting to Exchange with a blackberry to get the full blown experience. You can setup IMAP or POP too, but you won't get calendar, notes, etc. It also depends on if you exchange administrators have those services available.
