Position background png image? - ie6 problem?

HEy Guys,

Im using the following to set and position a png bg:

#mbg_left {
background-image:url(…/images/mobo_m.png);
background-repeat:no-repeat;
background-position:top left;
width:900px;
height:130px;
margin:0px;
padding:0px;
float:left;
}

any sort of alignment rules seem to be totaly ignored in i56 …any ideas?