Hi,
What version of AutoCAD do you use?
AutoCAD versions before 2004 will not plot shading, just hidden line even if the viewport os showing the object as shaded..
AutoCAD 2004 included a lovely new option of printing shadings and renderings. The viewports now have an all new Shadeplot property, which dictates how the shading is to be printed. If you have a copy and it's not working, check the shadeplot settings on the Plot tab on the Options dialog box or of the viewport itself..
If you don't use 2004, then the only real option, that I can think of, is to use the saveimg command and save the image. Then insert the new image as a raster image and plot that way.
Depending on what photo-editing software you may have, you may be able to print to PDF from there..
Anyway, I hope this helps..
Cheers,
Paul @ basepoint designz..
basepoint designz
renegade@bpdesignz.com