I got the requirement that based on preferred name the welcome name should come.
Go to Shared Services Administration: SSP1 > User Profile and Properties > View User Profiles
Modify ur preferred name as per screenshot
Refer How to modify profile properites
Go to My site click on details link and modify ur name filed with ur prefer name.
Run the below cmd
After the sync has been performed the User Info table will be updated with the values from the My Profile details.