Let it be useful to someone else like me...
For Adding a MenuItem
.red #slatenav ul li#Home a{
background: url(MyImages/ISG_Back_Img.jpg) no-repeat top center;
width:70px;
}
.red #slatenav ul li#Home a:hover{
background: url(MyImages/ISG_Fore_Img.jpg) no-repeat top center;
}
For SubMenu to AboutUs MenuItem
<li><a href="#" title="css menus">About Us</a>
<ul>
<li><a href="#" title="css menus">Company</a></li>
<li><a href="#" title="css menus">Management</a></li>
<li><a href="#" title="css menus">Mission & Values</a></li>
<li><a href="#" title="css menus">Contact Us</a></li>
</ul>
</li>