The username/password field on the Advanced tab specify the Windows user credentials that the process will run under.
http://www.kinook.com/VisBuildPro/Ma...dvancedtab.htm
The StarTeam username/password must be passed on the command-line to stcmd. Use the built-in StarTeam action.
http://www.kinook.com/VisBuildPro/Manual/starteam.htm