ORD C# add references to corridor

Hello again,

We are working on a .NET application to produce corridors. We are working with ORD and associated SDK.

We have managed to create the corridor and the template drop and we want to add "External References" to corridor objects.

I have searched the documentation but have not found anything regarding this. It is a type of point control, but it is not available in the "BaseCorridorElement", there are only the CurveWidening, EndConditionException, ParametricConstraints and PointControl.

Please see the attached annotated screen capture. In the screen capture the references have been attached manually.

All references are named and featurized and are used as switches in templates.

All entities are in the current DGN.

Thank you in advance for any suggestions.