The team areas are not in the process template. They are in the DB. If you create a project based on a Out-of-the-Box process template e.g."Scrum" the team areas are created in the initialization phase of the project. This is more like a script which runs.

This means if you want to have a process template with predefined team areas you have to customize the inizialization phase in the process template and not just create team areas in the template project area.