Create a Profile from Geometry in a Reference File

I have a dgn file containing an alignment with vertical geometry referenced into a work file. I would like to create a profile of the geometry in my work file, the problem is that the profile view only shows the vertical geometry. It does not show a line for the terrain even though it is set active. Is there a step that I'm missing or do I have to create the profile in the dgn that contains the original alignment? Thanks in advance!