this module is okay in dnn_4.4.0 and ajax previous version.

when I update to dnn4.5.1.I use cascadingdropdown in dnn_4.5.1,
if I use scriptmanager in the module ,I got a error.
[only a instance].
if I donot use scriptmanager in the module
I got another error
[The control with ID 'CascadingDropDownProv' requires a ScriptManager on the page. The ScriptManager must appear before any controls that need it.]
by the way .
my page_load like that

protected void Page_Load(System.Object sender, System.EventArgs e)
{
try
{
if (DotNetNuke.Framework.AJAX.IsInstalled())
{
DotNetNuke.Framework.AJAX.RegisterScriptManager();
ScriptManager objScriptManager = ScriptManager.GetCurrent(this.Page);
ServiceReference objServiceReference = new ServiceReference();
objServiceReference.Path = @"~/DesktopModules/IDCard/IDCardWebService.asmx";
objScriptManager.Services.Add(objServiceReference);
}




}
catch (Exception exc) //Module failed to load
{
Exceptions.ProcessModuleLoadException(this, exc);
}

}