Problem storing email passwords in Outlook 2002 & Vista

Since upgrading to Vista, I reinstalled Outlook 2002 and setup all my email
accounts and then imported my settings and .pst files from my previous
version of XP.

All my email accounts are working and the account settings panel in Outlook
displays the username and stored password for each account.

However, every time I open Outlook and press the send/recieve button, it
asks me for my password for each of the POP3 servers.

It never asked me to do this when running it under XP, the remember password
box is ticked but it does not seem to make any difference, it still asks for
the passwords evey time.

Any ideas what the problem may be?