Seems OK. Leaving files on the server implies that they are downloaded in a new Outlook instance. That keeps track of the last time it did it (never) and downloads every after that (all).
The easiest way: just let it do what it wants to do. It's one time only. If it's more than 2 GB, delete enough files from the server to keep it manageable.
Or find out where that timestamp is being stored (I suppose somewhere in the account properties in the registry) and use regedit to change it. I don't know where it is, but I'm sure Microsoft support can tell you if you make the call and pay for it.
One of the greatest problems I've had in switching computers is in setting up a new Outlook (2003) on a new system. I've tried copying .PST files to the new directories and opening them there and that seems to work -- that is, until the system begins downloading thousands of files from the mail server (the setting had been set to "Leave Messages On the Server"). Each time I connect, it begins the downloading process and I'm also unable to close the other .pst files that are open. My only option is to "Close All."
So I have three Personal Folders open and can't close any of them individually. Exporting the files does nothing (got a 32K file from a file that's over 2 gigs). The only thing I can find on the MS site is how to convert from other programs, not converting from one Outlook Office program to another.
Any of you system ops know what I should do?