i have done the CSS like below
.myStyle
{
background-image: url('Buttons/buttonBackground.png');
}
.myStyle1
{
background-image: url('Buttons/menuBack.png');
}
and My menu
<asp:Menu ID="Menu1" runat="server" CssClass="myStyle"
DynamicHorizontalOffset="2" Font-Names="Verdana" Font-Size="0.8em"
ForeColor="#7C6F57" Orientation="Horizontal" StaticSubMenuIndent="10px"
DataSourceID="SiteMapDataSource1" StaticDisplayLevels="2">
<StaticSelectedStyle BackColor="#CC00CC" />
<StaticMenuItemStyle CssClass="myStyle" HorizontalPadding="5px" VerticalPadding="2px"
BackColor="#F3F3EE" />
<StaticHoverStyle CssClass="myStyle1" BackColor="#CC00CC" ForeColor="White" />
<DynamicHoverStyle CssClass="myStyle" BackColor="#CC00CC" ForeColor="White" />
<DynamicMenuStyle BackColor="#F7F6F3" />
<DynamicSelectedStyle BackColor="#CC00CC" />
<DynamicMenuItemStyle HorizontalPadding="5px" VerticalPadding="2px"
BackColor="#F3F3EE" />
<StaticHoverStyle CssClass="myStyle" ForeColor="White" />
<Items>
....
....
And Now it is work like a charm...
May be it will help other like me..