ciao alex 
scusa ...ho solo generato il sito di default che vs crea...cmq
...questo è il menù e si trova in master page!
<div class="clear2 hideSkiplink">
<asp:Menu ID="NavigationMenu" runat="server" CssClass="menu"
EnableViewState="false" IncludeStyleBlock="false" Orientation="Horizontal"
DataSourceID="SiteMapDataSource1" StaticDisplayLevels="2">
<DynamicMenuStyle CssClass="IE8Fix" />
<Items>
<asp:MenuItem NavigateUrl="~/Default.aspx" Text="Home page"/>
<asp:MenuItem NavigateUrl="~/About.aspx" Text="Informazioni su"/>
</Items>
</asp:Menu>
<asp:SiteMapDataSource ID="SiteMapDataSource1" runat="server" />
</div>
...questo il CSS...
/* TAB MENU
----------------------------------------------------------*/
.IE8Fix
{
z-index: 100000;
}
div.hideSkiplink
{
background-color: #3a4f63;
width: 100%;
z-index: 100000
}
div.menu
{
padding: 4px 0px 4px 8px;
z-index: 100000
}
div.menu ul
{
list-style: none;
margin: 0px;
padding: 0px;
width: auto;
z-index: 100000
}
div.menu ul li a, div.menu ul li a:visited
{
background-color: #465c71;
border: 1px #4e667d solid;
color: #dde4ec;
display: block;
line-height: 1.35em;
padding: 4px 20px;
text-decoration: none;
white-space: nowrap;
z-index: 100000
}
div.menu ul li a:hover
{
background-color: #bfcbd6;
color: #465c71;
text-decoration: none;
z-index: 100000
}
div.menu ul li a:active
{
background-color: #465c71;
color: #cfdbe6;
text-decoration: none;
z-index: 100000
}
...default con OWC11
...così...?