othervars

Where can I write othervars for Flowplayer (e.g. image preview)?

  print swf('media/video.flv',
    array(
      'params' => array('width' => '320', 'height' => '260'),
      'othervars' => array('image' => 'images/media/preview.jpg'),
   )
 );

I can write image=images/media/thumbnails/video-preview.jpg to Flashvars field for JW player, but for Flowplayer it dosn't work.
Thanks