Use rectangles, fill with solid color and don't slice the areas. Export as CSS and images.
Thank you, Jim.
Is there a general rule to follow as to when you should or should not use a slice for identifying <div>s on your page?
Non-sliced images will be ignore when exporting. Fireworks rectangles will be converted to divs unless they are sliced, then they become graphics.
One exception to this rule is the three-slice technique. If you add three slices to a rectangle, FW will understand that you want a expandable container with a repeating background image
If you have not done so already, please read these articles:
While they all reference CS4, the basic concepts remain the same. Indeed, many of the new features in the CSS export for CS5 are thanks to Matt Stow. His is the third article in the list.