Hello,
Please check these article's.
https://www-secure.symantec.com/connect/forums/domain-joining-thorough-rtsm
https://www-secure.symantec.com/connect/forums/domain-joining-through-system-configuration-itms-75
https://www-secure.symantec.com/connect/forums/adding-workstation-domain-0
https://www-secure.symantec.com/connect/forums/how-do-you-use-system-configurations-join-domain
https://www-secure.symantec.com/connect/articles/adding-computer-domainou-deployment-7x-0