Fadding color with fireworks 8.0?

Hi all,

I've a newbie to graphic design, but not web site coding. I'm using Fireworks 8.0 from Adobe.

What I'd like to do is great a small graphic to be used as a background via CSS. I'd like this image to have a 'fading' or gradual color changing going from say blue to white from one end to the other. Or blue to transparent if possible.

Any tutorials, step by step for newbies on how to do this? I want to mimic this attached gif, but instead of a fade from green...make it a fade from dark blue. Would it be easier to just change this gif?

Thanks!