Frédéric,
I'm not sure what it is exactly you're trying to do. If you are looking to automate an XP install, you should read what Micro$oft has to say. http://www.microsoft.com/technet/treeview/default.asp?url=/TechNet/prodtechnol/winxppro/deploy/depovg/depxpii.asp If you plan to clone the machines, you'll need to SysPrep them to give them unique SIDs. SysPrep allows for some values to be automated with SysPrep.inf file.
Since the computers need to join the domain, I see no value in trying to hack the name in place.
I use the PowerQuest PowerDeploy suite of tools http://www.powerquest.com/ to deploy and manage.
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