ModalPopupExtender + FileUpload + Show Image on Page

Hello, 

  I am trying to open a popup window on a button click "Upload" thru ModalPopupExtender. Below "Upload" btn I have an Image control to display the selected image.

In the popup window I have FileUpload. On click of FileUpload button, in code behind I want to show the image in the popup Image Control "showPanImg" & then when the user clicks "Set" btn of popup, I want to save the image to server & show in the form in Image control. I have "SEt" & "Cancel" btns in poup window. But once on Upload of FileUpload btns is clicked and control is gone to code behind, then the popup is not visible.

My Upload Btn & Image Control code :

<td><asp:LinkButton runat="server" id="panBtn"
                        CssClass="popup_a btn menu-green">Upload PAN<span class="glyphicon glyphicon-chevron-down"></span></asp:LinkButton></td><td><asp:Image runat="server" ID="panImg" BorderStyle="Ridge" BorderColor="Turquoise" Width="100px" Height="100px" /></td>

On clicking "Upload PAN" btn, a popup is opened using ModalExtender...

<ajaxToolkit:ModalPopupExtender ID="pan" runat="server"
            TargetControlID="panBtn" PopupControlID="view_PanImages_popup"
            RepositionMode="RepositionOnWindowResizeAndScroll" DropShadow="true"
            PopupDragHandleControlID="uploadPanImage"
            CancelControlID="cancelPan"
            BackgroundCssClass="modalBackground"></ajaxToolkit:ModalPopupExtender>   

The Panel of Popup :

<asp:Panel id="view_PanImages_popup" CssClass="modalPopup" runat="server" Width="450px" Height="270px"><asp:Label id="uploadPanImage" runat="server" CssClass="pop-title">Upload PAN Image</asp:Label><table class="table" style="width:100%;" ><tr><td><asp:FileUpload runat="server" ID="panUploader" /><asp:Button runat="server" ID="panUploadBtn" Text="Upload" OnClick="panUploadBtn_Click" /></td><td><asp:Image runat="server" ID="showPanImg" BorderStyle="Ridge" BorderColor="Turquoise" Width="100px" Height="100px" /><%--                    	    <div id="showimages" style="width:150px;height:100px;">No images found</div>--%></td></tr><tr><td colspan="2"><asp:Label ID="panUploadStatusLbl" Text="" runat="server" CssClass="greenText" ></asp:Label>  <%--CssClass="error"--%></td></tr></table><div class="one-row" style="text-align:right; margin-right:10px;"><asp:LinkButton ID="okPanImg" runat="server" PostBackUrl="#" CssClass="btn menu-blue"
                        Style="background-color: green;" OnClick="okPanImg_Click"><span class="glyphicon glyphicon-ok"></span> Set </asp:LinkButton>   <asp:LinkButton ID="cancelPan" runat="server" CssClass="btn cancel_button"  ><span class="glyphicon glyphicon-remove"></span> Cancel </asp:LinkButton>  </div></asp:Panel>

In Code-behind, On fileUpload btn :

        // Upload PAN Card Image
        protected void panUploadBtn_Click(object sender, EventArgs e)
        {
            if (panUploader.HasFile)
            {
                try
                {
                    string path = Server.MapPath("~/CRMImages/");
                    string mypath = "~/CRMImages/";

                    if (panUploader.PostedFile.ContentType == "image/jpeg")
                    {
                        if (panUploader.PostedFile.ContentLength < 102400)
                        {
                            string fileName = Path.GetFileName(panUploader.FileName);
                            panUploader.SaveAs(Server.MapPath("~/CRMImages/") + fileName);  //IN SET
                            panImg.ImageUrl = mypath + fileName;    // SHOW IN FORM IMAGE - THIS TO BE DONE IN SET CLICK
                            showPanImg.ImageUrl = mypath + fileName;  // SHOW THE IMAGE IN POUP
                            panFileUrlTxt.Text = mypath + fileName;   // Saves the path in a textbox
                        }
                        else
                        {
                            panUploadStatusLbl.CssClass = "redText";
                            panUploadStatusLbl.Text = "File has to be less than 100kb";
                        }
                    }
                    else
                    {
                        panUploadStatusLbl.CssClass = "redText";
                        panUploadStatusLbl.Text = "Only JPEG files are accepted";
                    }
                }
                catch (Exception ex)
                {
                    panUploadStatusLbl.CssClass = "redText";
                    panUploadStatusLbl.Text = "File could not be uploaded. Error occured: " + ex.Message;
                }
            }
        }

        protected void okPanImg_Click(object sender, EventArgs e)
        {
// THIS IS NEVER FIRED, AS ONCE ABOVE EVENT IS FIRED, THE POPUP IS UNLOADED, SO NO CHANCE FOR THIS EVENT
            if (panFileUrlTxt.Text.Length > 0)
            {
                panImg.ImageUrl = panFileUrlTxt.Text;
                //File.Copy(panFileUrlTxt.Text, Server.MapPath("~/") + panFileUrlTxt.Text);
            }
        }

I just want to simply have my FileUpload control in popup & show the selected file in POPUP & once user is confirm, click "Set" btn in popup & show in form.  How to make the popup be shown even after FileUpload upload btn event is fired on server. Currently, on FileUpload upload btn (after code-behind) the popup is unloaded & have no chance to click "Set" or "Cancel" btns ??

Can you please help me out. Any help is highly appreciated.

Thanks