Design 3D CX now supports normal maps as well as bump maps, starting with v7. Normal mapping uses color information, and is more sophisticated and powerful than bump mapping.
To use a normal map, open the Image Texture dialog. Import the normal map into the Bump/Normal channel, then enable "Use Image as Normal Map" in the channel's drawer settiings. For more information see Chapter 9 in the User Guide.
With normal maps, you'll notice that you don't need to set very high values compared to bump maps. Where you may use 100-200% for a bump map, you may find that a normal map setting of 25-50% works well.
You can use your own normal map, or generate one using the Generate Map button in the Image Map dialog. There are also several third party applications and Photoshop plug-ins available for transforming regular image maps into normal maps.
There is a helpful discussion about normal maps; and third-party creation plug-ins and applications on the StrataCafe.com. It is located here.