Some extra Reporting Service Parameters

<rsweb:ReportViewer ID="rptLetter" runat="server" ExportContentDisposition="AlwaysAttachment" 
       Height="475px" ProcessingMode="Remote" PromptAreaCollapsed="true"
       ShowPromptAreaButton="false" SizeToReportContent="True" Width="100%" ShowFindControls="false"
       BackColor="#ededed">
        <ServerReport ReportPath="/Reports/Letter" ReportServerUrl="https://reportserver" />
        </rsweb:ReportViewer>

  Dim MyDate As New ReportParameter("date", PrintDate)
  Dim p() As ReportParameter = {MyDate}

  rptLetter.ServerReport.ReportPath = "/Reports/" & ReportName
  rptLetter.ServerReport.ReportServerCredentials = New ReportViewerCredentials(
       "username", "password", "domain")
  rptLetter.ServerReport.SetParameters(p)
  rptLetter.ServerReport.Refresh()
  rptLetter.Visible = True