Openroads ConceptStation and DGN Exported files.

The roadway elements that get exported into a DGN format and Extended Elements.  As such, I'm having difficulty using these elements in the file, for instance I can snap to it and manually draw a boundary to it, but I can't flood a shape with the element as a boundry, or extract a boundry (since its not a mesh or surface), or clip a portion (such as with a fence clip) or do anything to those elements in the file.  

Is there anything I can do with the elements within the file that makes them more user friendly, and manipulatable in the dgn environment once its exported.  If not, what is the intended use case of exporting it as a DGN other that simply referencing as is?