Can I have a muted video with UnMuteOverlayButton, but without autoplay?

Hi,

I’m trying to embed video without autoplay, but I want to mute it on the start and I want to have unMuteOverlayButton. I have embeded video with this code, but button does not show:

  <script type="text/javascript">
    kWidget.embed({
      targetId: '...',
      wid: '...',
      uiconf_id: '...',
      entry_id: '...',
      flashvars: {
        autoMute: true,
        autoPlay: false,
        unMuteOverlayButton: {
          plugin: true,
        },
      },
    });
  </script>

Is it possible to use unMuteOverlayButton without autoplay?