I'm having trouble getting a PDF export to work when I put my grid into a User Control. The same code works fine when it lives in its own aspx page. Are there any known issues with this?

- All the User controls are inside a WebAsyncRefreshPanel:

<igMisc:WebAsyncRefreshPanel ID="webPanel" InitializePanel="webPanel_InitializePanel" runat="server">
    <ADV:AvailSearches ID="AdvAvailSearches" runat="server" EnableViewState="true" /><br />
    <asp:Placeholder ID="AdvCriteriaContainer" runat="server" EnableViewState="true" />
    <br />
    <asp:Placeholder ID="AdvResultsContainer" runat="server" EnableViewState="true" />
</igMisc:WebAsyncRefreshPanel>

In the User Control which I load into AdvResultsContainer, I have:

In the aspx page, I have:

        <igtbldocexp:UltraWebGridDocumentExporter ID="UltraWebGridDocumentExporter1" runat="server" />
        <igtblexp:UltraWebGridExcelExporter ID="UltraWebGridExcelExporter1" runat="server" />

In the code behind, I have this method being called by an event tied to a LinkButton:

protected void PDFExport_Click(object sender, EventArgs e)
{
    try
    {
        UltraWebGridDocumentExporter1.ExportMode = Infragistics.WebUI.UltraWebGrid.Exporter.ExportMode.Download;
        UltraWebGridDocumentExporter1.Format = Infragistics.Documents.Report.FileFormat.PDF;
        UltraWebGridDocumentExporter1.DataExportMode = Infragistics.WebUI.UltraWebGrid.DocumentExport.DataExportMode.DataInGridOnly;
        UltraWebGridDocumentExporter1.Export(mygrid);
    }
    catch (Exception ex)
    {
        throw ex;
    }
}

When I debug this, it goes to Export(mygrid) and throws this Exception (as if it lost the handle to the object???)

System.NullReferenceException was caught
  Message="Object reference not set to an instance of an object."
  Source="Infragistics2.WebUI.UltraWebGrid.DocumentExport.v8.1"
  StackTrace:
       at Infragistics.WebUI.UltraWebGrid.DocumentExport.CssClassCollection.AddStyles(UltraWebGrid grid)
       at Infragistics.WebUI.UltraWebGrid.DocumentExport.UltraWebGridDocumentExporter.RenderDocument()
       at Infragistics.WebUI.UltraWebGrid.DocumentExport.UltraWebGridDocumentExporter.Export()
       at Infragistics.WebUI.UltraWebGrid.DocumentExport.UltraWebGridDocumentExporter.Export(UltraWebGrid grid, ISection section)
       at Infragistics.WebUI.UltraWebGrid.DocumentExport.UltraWebGridDocumentExporter.Export(UltraWebGrid grid, Report report)
       at Infragistics.WebUI.UltraWebGrid.DocumentExport.UltraWebGridDocumentExporter.Export(UltraWebGrid grid)
       at GPMS.Dashboard.UserControls.SalesDetail_Results.PDFExport_Click(Object sender, EventArgs e) in C:\GPMS\GPMS\Dashboard\UserControls\SalesDetail_Results.ascx.cs:line 293

Line 293 is the call to Export()