When migrating older legacy styles and drawings forward, one of the more time consuming tasks is dealing with any program changes and/or new features. A good example of this would be migrating an existing wall style library from ADT 3.3 and lower to ADT 2006.
One of the best improvements for walls was the addition of materials to ADT 2004, giving us more "global" display control over the linework, plan, surface and section hatch as well as the sectioned body and boundary control. Unfortunately you may find that updating your existing library by going through each wall style and adding/editing the material definition to be time consuming. The good news is you can use the "Apply Material" tool to apply a particular material at the style level or object level quickly and easily.
You will find this tool on the Design tab of the tool palettes in ADT 2006, called "Material". To get a better idea of how this works, you may wish to review the Applying Materials video example.