On initial sync, only messages that are not older than 7 days are forwarded to the device, and a maximum of 350 messages can be forwarded. Calendar appointments are synchronized if they are not older than 30 days. Re-occurring appointments will be synchronized if the end date is in the future or within the last 30 days.
This is a default setting of the BlackBerry Server and it cannot be modified in the shared environment.
Please note that if you reactivate the same device for an existing user, message prepopulation will not occur. This happens because the server has the device PIN number saved and it doesn't attempt to reload messages to the same device.
Message prepopulation occurs each time you activate a new user or when an existing user activates a new device.