<style>
body{background:url(http://image.zcool.com.cn/cover/11/59/1289761540734.jpg);}
.div { 
filter:alpha(opacity=50);/*IE*/ 
opacity:0.5;/*Mozilla*/ 
} </style> 

外层透明内层不透明 
<div class="" style="width:710px;height:73px;position:absolute;"> 
<div class="" style="width:100%;height:73px;position:absolute;filter:alpha(opacity=40);opacity:0.5;background000000;z-index:-10;"></div>
<div class="" style="position:absolute;z-index:10;" mce_style="position:absolute;z-index:10;">558866<br/><br/>afadfasadf<br/></div> 
</div>

------解决方案--------------------
我这个是按钮的 背景透明和你的性质一样哦，你看看我试了IE6行的
  <input type="submit" style="background:url('/images/order.png') no-repeat!important;background-image:none;filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(src='/images/order.png',sizingmethod=scale); width:128px; height:33px;line-height:0;text-indent:-9999px;border:none;cursor:pointer;" name="action_order_now" value="Order Now" />

------解决方案--------------------
C# code
 <input type="submit" style="background:url('/images/order.png') no-repeat!important;background-image:none;filter:progid:DXImageTransform.Microsoft.AlphaImageLoader(src='/images/order.png',sizingmethod=scale); width:128px; height:33px;line-height:0;text-indent:-9999px;border:none;cursor:pointer;" name="action_order_now" value="Order Now" />