In beta 2, xml-script is maintained in the value-added bits. So, in order to use it, you need to insert the client side script file needed to support its parsing and processing. If you”re using a simple HTML page, just drop the previewscript.js file on that page; if you”re using an ASP.NET page, then you can load it through a ScriptReference:
<asp:ScriptManager runat=”server” id=”manager”>
<asp:ScriptReference Assembly=”Microsoft.Web.Preview” Name=”Microsoft.Web.Resource.ScriptLibrary.PreviewScript.js” />
btw, the name of resource can be easily obtained through reflector.