Resize Background didnt work IE

I'm trying to resize my background but didnt work in IE :/
works in Safari, Firefox, chrome....
im using this css to resize

html {
background:url(Layout_JaponesaBaby_-02.png) no-repeat center center fixed;
-webkit-background-size: cover;
-moz-background-size: cover;
-o-background-size: cover;
background-size: cover;
}

http://benjax.com.br/lojademo/topic/11-nossa-historia.aspx
this is the website test

are u guys know another code?

Thanks

try clearing the browser cache in IE, sometimes it just doesn't want to display your changes