You can't do what you want to do.
Message pre-population for a newly activated device only puts messages from the previous 5 days, or 200 messages, whichever is greater.
You can adjust the pre-pop settings on BES to set this to a maximum of 14 days or 750 messages.
How do I adjust message pre-population? - BlackBerryFAQ
You will not be able to put the entire contents of the Inbox back on the device.