Let me clarify:
You should import your alg and dtm into OpenRoads (MicroStation). Then use the OpenRoads commands to create the profiles and cross sections. Once the design is complete, you will need to export the data back out to a dtm and alg so that you can complete the drafting and plans production. Eventually everything will be done in OpenRoads without the needs for external data files (dtm, alg, etc.) - we just are not quite there yet with the software development.