When SolidWorks exports to PDF and converts your "Shaded with Edges" views to simply "Shaded," (SW2010 SP4), the solution is to hide the views and then unhide them. After that, saving shows the views correctly.
That doesn't always work. I'll get back to you when I've found an alternate method.
1. Close SW, restart program.
2. Hide views that won't save with edges
3. Save SLDDRW as PDF
4. Show views that won't save with edges
5. Save SLDDRW as PDF (Overwrite previous)
6. Enjoy PDF with edges shown
7. Bask in your victory.
Did you tried changing PDF export options??
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