Got it working
Host page code
<body>
<form id="form1" runat="server" style="height:100%">
<div id="silverlightControlHost">
<object data="data:application/x-silverlight-2," type="application/x-silverlight-2" width="950" height="650">
SL xmal code
<UserControl
x:Class="xxxxxxxxxxxx"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:data="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"
xmlns:controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"
Width="950" Height="650" mc:Ignorable="d" > //This is the part of concern
//etc