Enable creating of built-in related objects (objects without nodes) by enabling the ini-setting below (site.ini):
Create class with ObjectRelationList datatype attribute. Create instance of the class, the content object with related object (without node) inside it. And then try to copy that object by using either 'content/copy' or 'content/copysubtree' functionality.
The ObjectRelationList attribute of the result copy of the object will point to built-in related object of the source object. The expected result is that copy of related object should be created also while copy operation, and the relation list of the result object should point on that copy.