Setting service and Registry values

Is it possible to do the following via InstallScript?:
1) Set the login and password values for an NT Service
2) Set the user permissions to a registry key
For reasons too complicated to go into here, I cannot use the InstallShield "Install NT Service" feature for a component. I would like to use InstallScript to set the login and password values for an NT service, and also grant "Full Control" access to a registry key for a user name that the user will input at install time. Is this possible?

Thanks,
Bob Rouse
Netuitive, Inc.

BobRouse