outlook downloads mail from exchange each time mail is opened

[kiess]

Conf : outlook 2000 with exchange 2003 on different site.

When outlook opens a mail from exchange for the first time, the mail is
downloaded - that is ok.

The problem is that each time the mail is opened, outlook re-downloads
it from exchange (Even if off-line synchronization is set).

This is a real problem for users in distant sites (through VPN) because
a large attachment can take a long time to be downloaded.

Is there a way for outlook not to act like that ?
perhaps a setting on the exchange 2003 server side ?

Thanks.

 

[kiess]

PS : I know that oultook dowloads the mail again because I can see it
with tcpdump on the firewall.