ASP.Net AutoCompleteExtender VB WebMethod not firing - why?

Definitely at my wits end here. This should be simple. In a page to create new user accounts, we have a database with a little of allowable users. To streamline getting the Email address of the new user correct, we want to use an AutoComplete extended textbox.

Now I know that WebMethods are working because I have a cascading-drop-down tied to web methods in another page.

As I'm just starting on this page, the code is simple.

The page itself:

<cc1:ToolkitScriptManager ID="ScriptManager2" runat="server"/>
<p></p> Please enter new user's Email: 
<asp:TextBox ID="txtUser" runat="server" />
<cc1:AutoCompleteExtender runat="server" ID="autUser" TargetControlID="txtUser" 
      开发者_Go百科  ServiceMethod="ScanGALUsers" ServicePath="~/AutoScan.asmx"
        MinimumPrefixLength="3" CompletionSetCount="150" /> <p></p>

The .asmx file is simple:

<%@ WebService Language="VB" CodeBehind="~/App_Code/VB_Code/AutoScan.vb" Class="AutoScan" %>

The WebMethod:

<System.Web.Script.Services.ScriptService()> _
<WebService(Namespace:="http://tempuri.org/")> _
<WebServiceBinding(ConformsTo:=WsiProfiles.BasicProfile1_1)> _
<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
Public Class AutoScan
    Inherits System.Web.Services.WebService

   <WebMethod()> _
    Public Shared Function ScanGALUsers(ByVal strPrefix As String, ByVal intMaxCount As Integer) As String()
        Dim arlResults As New ArrayList
        Dim intCount As Integer
        Dim dt As DataTable
        Dim colParameters As New SortedList
        SysDA.LogDebug("ScanGALUsers called with parameters: " & strPrefix & " and count of " & intMaxCount.ToString)
        ... Deleted for brevity ...
        If intCount > 0 Then
            Dim arrResults(intCount - 1) As String
            arrResults = arlResults.ToArray(GetType(System.String))
            Return arrResults
        Else
            Return Nothing
        End If
    End Function

End Class

I'm not even getting to the LogDebug statement. I've used all the same boilerplate code (Inherits, the 'WebService' tags, etc) that worked in the other WebMethod with the appropriate changes to the Class name but this really has me stumped.

What am I missing that I'm not even making it to the method?

Did you ever resolve this issue? Have you tried removing Shared from your WebService declaration? This has worked for me before (and I don't know why!).