Well, I did not need the controller component and hence did not use it for TA's. The business delegate + servicelocator components would be enuff to handle the right service. I however, had another a component for session handling which would basically maintain session data to be sent to-and-fro from TA's desktops. I handled session in the web tier instead of SFSB's.
If u really needed controller function, you can design it appropriately. Hope that helps