Hi Dan,
As you have discovered, no that won't work. The only position that has system behavior associated with it in RC06 is the system-defined Manager position for a Service Team.
However, it is the Service Manager Site Permission that enables a user to reassign tasks, not the Manager position for a Service Team. What the Manager position gets you is the convenience of seeing the Service Team, and all of its members, in one place in ServiceManager.
Any user with the Servic