Dynamic Menu Items - ASP.NET

Jeg bruger ASP.Net og VB

Jeg har en ASP menu:
Dim ds As DataSet = GetDataSetForMenu()
        Dim menu As New Menu()
        Dim MainMenuItem As New MenuItem
        Dim SubMenuItem As New MenuItem

        Dim parentItem As DataRow
        Try
            MainMenuItem = New MenuItem("|")
            'menu.CssClass = "VerticalLine"
            menu.Items.Add(MainMenuItem)

            For Each parentItem In ds.Tables("MenuLow_Tbl").Rows
                MainMenuItem = New MenuItem(CStr(parentItem("MenuText")))
                MainMenuItem.NavigateUrl = CStr(parentItem("NavigateUrl"))
                menu.Items.Add(MainMenuItem)

                Dim childItem As DataRow
                For Each childItem In parentItem.GetChildRows("Children")
                    SubMenuItem = New MenuItem(CStr(childItem("SubMenuText")))
                    SubMenuItem.NavigateUrl = CStr(childItem("NavigateUrl"))
                    MainMenuItem.ChildItems.Add(SubMenuItem)
                Next childItem

                MainMenuItem = New MenuItem("|")
                'menu.StaticMenuItemStyle.CssClass = "VerticalLine"
                'menu.DynamicMenuItemStyle.CssClass = "VerticalLine"
                menu.Items.Add(MainMenuItem)
            Next parentItem

            menu.Orientation = Orientation.Horizontal
            '1st level menu styles
            menu.StaticPopOutImageUrl = "gfx/nav_arrow_down.gif"
            menu.StaticMenuItemStyle.CssClass = "MainLow"
            menu.StaticHoverStyle.CssClass = "MainLowHover"
            '2nd level menu styles
            menu.DynamicPopOutImageUrl = "gfx/nav_arrow_down.gif"
            menu.DynamicMenuItemStyle.CssClass = "SubLow"
            menu.DynamicHoverStyle.CssClass = "SubLowHover"
        Catch ex As Exception
            LblMessage.Text = ex.ToString
            Response.Write(MySQL)
        End Try

        Panel1.Controls.Add(menu)
        Panel1.DataBind()

Med følgende CSS:
.MainLow
{
    font-family: Arial, 'Apex New Book' , Verdana, Tahoma, Sans-Serif;
    font-size: 12px;
    color: #ff0000;
    z-index: 2;
    padding: 5px 1px 5px 1px;
    margin: 0px;
}
.MainLowHover
{
    font-family: Arial, 'Apex New Book' , Verdana, Tahoma, Sans-Serif;
    font-size: 12px;
    color: #000000;
    z-index: 2;
    padding: 5px 1px 5px 1px;
    margin: 0px;
}

.SubLow
{
    padding: 2px 2px 2px 2px;
    margin: 0px;
    font-family: Arial, 'Apex New Book' , Verdana, Tahoma, Sans-Serif;
    font-size: 12px;
    color: #FF0000;
    background-color: #c0c0c0;
    border-bottom: #ffffff 1px solid;
    z-index: 5;
    white-space: normal;
}
.SubLowHover
{
    padding: 2px 2px 2px 2px;
    margin: 0px;
    font-family: Arial, 'Apex New Book' , Verdana, Tahoma, Sans-Serif;
    font-size: 12px;
    color: #000000;
    background-color: #c0c0c0;
    border-bottom: #ffffff 1px solid;
    z-index: 5;
    white-space: normal;
}

I IE8 vises childitems ikke. Er der nogen der ved hvorfor?
Hvis jeg trykker på kompatibilitetsvisning virker det.

/Stine