found a trick on http://www.noscope.com/journal/2005/...nderscore-hack

in stylesheet.css you can apply different styles swith IE or FF. My problem was with the space between logo and navMainWrapper. In FF was fine but in IE it breaks the design of the site. I add the style #navMainWrapper:

#navMainWrapper, #navSuppWrapper, #navCatTabsWrapper {
margin: 0em 0em;
background-color: #ffffff;
background-image: url(../images/navMain.gif);
background-repeat: repeat-x;
font-weight: bold;
color: #ffffff;
height: 1%;
width: 966px;
}

#navMainWrapper{
margin-top: 0px; /*default*/
_margin-top: -2px; /*only for IE*/
}

hope that helps.