How to specify Scope for AreasOfResponsibility.dat

Summary:

I'm trying to load Areas Of Responsibility for 250 employees, one of the requirements of which is to specify Position in the Scope.

I've attempted to reference PositionCode but get the error 'You need to enter a valid value for the PositionId attribute. The current values are E05120341001.'

I've therefore produced a report to get all the PositionIDs and reference these, but get the error 'The METADATA line can't be processed because the PositionID attribute is unknown for V2 version of the AreasOfResponsibility business object.'

What is the correct method to specify the Position? Do I need to specify an additional identifier to use Position, e.g. Business Unit?