If you have service reference (e.g. to an AJAX Enabled WCF Service) in your ScriptManager (or ToolkitScriptManager):
<asp:ToolkitScriptManager ID="ToolkitScriptManager1" runat="server">
<asp:ServiceReference Path="~/MotoService.svc" />
/// <reference name="MicrosoftAjax.js" />
/// <reference path="~/MotoService.svc" />
In code behind for WPF/Silverlight in Visual Studio you can use the key combination snippet (assuming defaults) ctrl-k then x then NetFX30 then either choose either a DependencyProperty or attached DependencyProperty.