plupload how to disable / enable Add files button?

Question

I've been trying pluploader out to front end upload files to my Photo gallery webpage and it works well. Basically just followed the examples on the website. But I would like to disable the Add files button initially until user has selected an upload destination "album" which they do by pressing a button click handler I implemented (see album-select onclick below). I have managed to disable the Add button in the constructor as shown, but I'm having no luck re-enabling it when user presses the album button. Any ideas how to implement re-enabling the Add files button from my own button press? Thanks!

<script type="text/javascript">

    var uploader = $("#upl").plupload({
      // General settings
      url : g_homeUrl + "get-from-browser/",
    
      // Maximum file size
      max_file_size : '10mb',
    
      // Specify what files to browse for
      filters : [
          {title : "Image files", extensions : "jpg,jpeg,gif,png"}
      ],
    
      // Sort files

      sortable: true,
    
      // Enable ability to drag'n'drop files onto the widget (currently only HTML5 supports that)
      dragdrop: true,

       // To disable Add files button. 
       buttons: {
        browse: false
      },
    
      // Views to activate
      views: {
          list: true,
          thumbs: true, // Show thumbs
          active: 'thumbs'
      }
    
    });
    
    uploader.init();

    uploader.bind('complete', function(up, fl){
      console.log('Completed uploading ' + fl.files.length + " files"); 
    });

    uploader.bind('error', function(up, err) {
      document.getElementById('console').innerHTML += "\nError #" + err.code + ": " + err.message;
    });

    document.getElementById('album-select').onclick = function(e) {
      albSet = e.target.dataset.album;
      var albTitle = e.target.dataset.title;
      var html = "Upload to album " + albTitle + "<br/>";
      html += "Click add files to select your images for upload";
      document.getElementById('console').innerHTML = html;
      // How to enable browse (Add files) button if disabled in constructor?
      //uploader.disableBrowse(false) says not a function??
    }
    
</script>