This support video shows the process for import two images from Google Earth to MXRoad using the same co-ordinate system.
In this video, Penrith NSW , Australia location is used in Google Earth, also some steps has been used from the following link:
http://communities.bentley.com/products/road___site_design/w/road_and_site_design__wiki/15117.how-to-convert-mesh-to-triangulation-model-and-display-contours-in-mx-road.aspx
Please let me know if you have any questions on the same.