Contour shapefile export to CAD. Preserve elevation values.

[AlexSandoval]

Hi I'm new working with ArcGIS and I'm having some trouble exporting to CAD.
I need to export terrain information to a CAD file. I have a shapefile with the terrain data that includes elevation values. When I use the export to CAD tool, the file does not preserve the elevation attributes and shows all the polylines with elevation = 0.
Is there a process I'm missing to assign the Elevation value from the shapefile to the Z Value in the CAD file?

I hope someone can help.
Thanks a lot!

[KelsiJurik]

I was having the same results when trying to export contour polylines to MicroStation DGN fornat until I started using a 3D seed file.  Also be sure that there is a column named "elevation" with the elevation values.  I found that the column "contour" in our early attempts was not interpreted as the elevation value of the contour.