Hi, I'm trying to create a horizontal menu where I can have a transparent gradient go over the top of the background color. I had this great idea to make a css menu, set the background color for <li> items to whatever I want (I would use a color picker & php/mysql to echo out the background color) then have a 30% transparent gradient sit on top of it. So if the background colours were set to white, black, dark red, light blue or khaki, they would look as below.
Hmm I can't post images?

Anyway I made an image in photoshop with a transparent background, then added a layer & filled it with a gradient & set opacity to 30%, but alas when I tried to save it, photoshop fliled the background with white, even if I saved as gif or png. Thus the background color can't be seen.

Is there any way to achieve what I am trying to do with photoshop or perhaps css?