moving user settings from one domain to another domain

Hello, we will be changing from an NT 4 domain to a new 2003 domain. we have a new DC server with users that we created from the NT4 domain. we have 98, 2000, xp stations on the old domain that will be adding to the new domain. when ever a new user logs in to a station on 2000 and xp, it creates a profile(c:\documents and settings\username.domain). is it possible to copy a profile of a user to another domain. I tried coping everything under the C:\documents and settings\username.olddomain to C:\documents and settings\user.newdomain but it did not work. I want all the users from the old domain to keep the setting they had on their computers. the profiles are saved on each computer for users that logon to the stations. any advise will be helpfull. thanks.