Hintergrundbild fixieren?

<style type="text/css">
<!--
td{color:#ffffff;}
a{color:#ffffff;font-size:15px;}
a:visited{font-size:15px;}
a:hover{font-size:15px;}
body{background-attachment:fixed;background-image:url(URL des Hintergrundes);}
td.nav{background-image:url();}
td.nav:hover{background-image:url();}
td.nav_heading{background-image:url();}
td.nav a{color:#FFFFFF;}
td.edit_below_nav{visibility:hidden;}
td.edit_header_full{background-image:url();}
td.headline2{background-image:url();}
td.headline{background-image:url();}
td.edit_content{background-image:url();}
div{color:#FFFFFF;width:100%;}
td.edit_content_top{background-image:url();}
td.edit_content_bottom{background-image:url();}
td.edit_content_bottom2{background-image:url();}
td.edit_rechts_sbg{background-image:url();}
td.edit_navi_headbg{background-image:url();}
td.edit_rechts_cbg{background-image:url();}
td.edit_rb_footer{background-image:url();}
td.shouty{background-image:url();background-color:transparent;}
td.shouty2{background-image:url();background-color:transparent;}
td.shouty3{background-image:url();background-color:transparent;}
td.shouty4{background-image:url();background-color:transparent;}
td.shouty5{background-image:url();background-color:transparent;}
td.edit_rechts_bottom{background-image:url();}
td.sidebar_heading{background-image:url();}
-->
</style>

body {background-image:url(HINTERGRUND URL);
background-repeat:no-repeat;background-position: center center;background-attachment: fixed;}
text-align:center; }