ASP.NET - ajax slideshow calling webservice with parameter

I want to use the ajax slideshow extender and got so far to use it with calling a range of images from database by coding an ID hard in the webservice. However I want to be able to pass a parameter to tthe webservice so I can get specific images. Code is below... Anybody ?

Code in aspx:

            <ajaxToolkit:SlideShowExtender ID="slideshowextend1" runat="server"
                TargetControlID="Image1"
                SlideShowServicePath="slidesservice.asmx"
                SlideShowServiceMethod="GetSlides"
                AutoPlay="true"
                ImageDescriptionLabelID="imageLabel1"
                NextButtonID="nextButton"
                PlayButtonText="Play"
                StopButtonText="Stop"
                PreviousButtonID="prevButton"
                PlayButtonID="playButton" />

Webservice:
Imports System.Web.Services.Protocols

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

    <WebMethod()> _
   Public Function GetSlides() As AjaxControlToolkit.Slide()
        Dim ds As System.Web.UI.WebControls.SqlDataSource = New SqlDataSource()
        ds.ConnectionString = System.Configuration.ConfigurationManager.AppSettings("apuraprovider")
        Dim mySelect As String
        Dim count As Integer = 0
        mySelect = "SELECT objectenfotos.object_ID, objecten.klant_ID, objectenfotos.fotonaam, objectenfotos.omschrijving " & _
        "FROM objectenfotos INNER JOIN objecten ON objectenfotos.object_ID = objecten.object_ID " & _
        "where objecten.klant_ID = myparameter

        ds.SelectCommand = mySelect
        Dim dv As System.Data.DataView = DirectCast(ds.[Select](New DataSourceSelectArguments()), System.Data.DataView)
        count = dv.Table.Rows.Count
        Dim slides As AjaxControlToolkit.Slide() = New AjaxControlToolkit.Slide(count - 1) {}
        Try
            For i As Integer = 0 To count - 1
                slides(i) = New AjaxControlToolkit.Slide("uploadlogos/mid/" & dv.Table.Rows(i)("fotonaam").ToString(), dv.Table.Rows(i)("fotonaam").ToString(), dv.Table.Rows(i)("omschrijving").ToString())
            Next
        Catch
            'some errorhandling
        End Try
        Return (slides)
    End Function

End Class