I have run into two small glitches when creating Silverlight designs in Expression Design and I got the fixes from the Product Team.  When you export a design to Silverlight XAML you may run into these problems:

  1. Viewport attributes are added to ImageBrushes elements.  Since Viewports are not supported in Silverlight, you should remove Viewport attributes from ImageBrush elements.
  2. Images filenames have \ slashes in the paths.  Replace the \ with / slashes (you can do a simple search and replace for \ characters.

I also got word from the product team that this will be fixed soon.  Yippee!