I looked at the Adobe page source code and saw
props.wmode= "opaque";
However, this line is embeded in Javascript. I don't use Javascript though.
Here's a piece of my code:
<object classid="clsid

27CDB6E-AE6D-11cf-96B8-444553540000" codebase="
width="584" height="235" title="slide-show">
<param name="movie" value="flash/slide-show.swf" />
<param name="quality" value="high" />
<param name="wmode" value="transparent" />
<embed src="flash/slide-show.swf" quality="high" pluginspage="
type="application/x-shockwave-flash" width="584" height="235">
</embed>
</object>
My flash object is a swf file. I have also tried setting one of those parameters above to:
<param name="wmode" value="opaque" />
but it's not working for Mozilla Firefox (it's working for Internet Explorer)