When you print a vector PDF, either by clicking on the "use high-accuracy HLR" option in the Print dialog, or by exporting a PDF via the Export>2D Image function, the SU view is exported as a 2D image with vector lines and flat-colour fills. It seems to me too that no settings in the shadow settings dialog, like the light and dark sliders, or the "use sun for shading" have any effect on the darkness and colours of the generated fills. I don't know if it is a bug, or just a feature lacking...
Anssi