CSS3 background-size属性在IE8中不起作用

Question

我在我的网站上使用过这个Hack，但我还是无法解决背景大小的问题，有人可以帮我解决这个问题吗？

filter: progid:DXImageTransform.Microsoft.AlphaImageLoader( src='../img/logo_sm.png', sizingMethod='scale'); 
-ms-filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader( src='../img/logo_sm.png', sizingMethod='scale')";

我的代码：

.dropdown-menu {
background-image: url(../pics/Responsive/dropdown-bg.png);
background-size: 100% auto;
background-position: top left;
background-repeat: no-repeat;
background-color: transparent;
top: 100%;
left: 10%;
position: absolute;
text-align: center;
border: 0;
box-shadow: none;
width: 1048px !important;
float: none !important;
margin: 0 auto !important;
top: 56px !important;
min-height: 200px!important;
border: 0 none !important;
padding: 10px 6% 0;
filter: progid:DXImageTransform.Microsoft.AlphaImageLoader(src='../pics/Responsive/dropdown-bg.png',sizingMethod='scale');
-ms-filter: "progid:DXImageTransform.Microsoft.AlphaImageLoader(src='../pics/Responsive/dropdown-bg.png',sizingMethod='scale')";

}