How to copy one master shape by code, standard copy throw an exception.

How to copy one master shape by code.
I try to copy one circuit components (master shape) in the same stencil.

var master = AssistantSettingsManager.BaseMasterShape.CopyTo(AssistantSettingsManager.BaseMasterShape.Parent);

The standard copy throw an exception "Aucotec.EngineeringBase.Client.MethodNotAllowedException" with method not authorized for this object.