This is really bugging me, mainly because there seems no logic for it. I am trying to slice up an image and export it accordingly, using 'alpha transparancy'. For some reason though, when I try to change the 'Matte' colour for this to work, fireworks keeps flicking it back to the nearest websafe colour.
The most frustrating thing is that I have done this thousands of times before with no problems, so what could be wrong?
If you want an exact matte color (non-websafe) with alpha transparency, make sure that you export the image with the exact matte color you want as the background. Then click on "alpha transparency" during export to get rid of the background color. The background color will then become transparent and your matte color should be an exact match.
If you try to export the image with the background already transparent - it won't work. It has to be the exact color you want the matte color to be.
I hope you figured it out by now, but just in case...
The thing with Fireworks is that you cannot select non-web safe matte colors, but if you export your image with the desired matte color as the back-ground color, you will automatically get the exact matte color you want when you select 'alpha transparency'.
The only thing you have to make sure is that when you are exporting the image, the background color is not an image. The back-ground color needs to be selected through 'modify - canvas color'.
To see want I mean, open a new window with a custom background color (non-websafe color), then type an anti-aliased word onto the canvas in white - any word. Click on export, then select 'alpha transparency', you will see that the matte color is the exact background color.