Outlook Express to Exchange 2003

I am looking to convert a single Outlook Express 6 mailbox to a Exchange Server 2003 and was wondering the best way to go about it. The mailbox is live and quite large (10gb in many folders) and minimizing downtime is a priority.

If I export everything to Outlook 2000 “offline” (before I connect the machine containing the mailbox to the domain), can I then add Exchange Server to the profile and go from there? Or am I limited to connecting to the domain and having the Outlook Express export function export everything to the Exchange Server directly (very slow and the mailbox is unusable during this time)?

Alternatively, can I take the .dbx files locally to the server running Exchange and import them from there?