Banner transp. backgr.dreamweaver?

Hi there,
I’m trying to make a html site with flash content.In my main html file I have placed a background image. There I won’t to place a banner made in flash on top. Is it possible to save the flash file so It won’t show it’s background color and I actually see the background image of the html file instead.How?

Hope anybody can help me out.Big thx in advance.