first time user accessing outlook

in our organisation we have little issue, when we create a new user, the scriopt create AD account as well as an email based on exchange 2003. however, when the user login for the 1st time to his machine and launch outlook it ask him to put the exchange details… how can we avoid this from ahppening, i know there is a tool in ecahnge, but i cant figure it out, any suggestions will be very much appreciated