i actually solved this, and found an error in the extending
fireworks documentation. after changing a few options in the
optimize palette, i took the history steps and converted them to
jsf to see what it was doing.
the documentation states that paletteTransparencyType is a
property of the ExportOptions object, when in fact it is not. the
correct property is paletteTransparency. wow....that had me
scratching my head for hours.
so the correct jsf would be:
var ex = new ExportOptions();
ex.exportFormat = "PNG";
ex.colorMode = "indexed";
ex.paletteTransparency = "rgba";