3D PDF not displaying all materials

Hello, when I'm trying to generate a 3D PDF I only get a few of the objects in the file to display materials (see below).

Some of the materials display correctly, but some do not??? I'm using the delivered PDF.pltcfg file for SS4, and have detached any pen tables. All materials are attached to the elements and it looks fine in the print preview window. All of the materials also display correctly when rendering an image.  I've tried all of the different combinations of display styles and 3D plotting display mode options, but I keep getting the same result. Why would some materials display and not others?

thanks,

Kevin

ms 08.11.09.829 Win 7 pro