Exchange 5.5 mailbox – .PST calendar syn

Ok, I have an Exchange 5.5 server running, and my users are running Outlook 2000 clients. I have configured the clients with .pst files, and incoming email is delivered to them, keeping the email from building up on the server. Problem: I need tohave my Exchange mailbox calendar synchronize with the .pst file calendar. Does anyone know how to do this? Or do you have a suggestion that would solve the issue? Primarily, this is an issue with users being able to synchronize their calendars with their Palm devices.