How can I have a visually active (checked), disabled toggle button in Bootstrap?

Bootply

I have a data-toggle checkbox group, where I'd like one (or more) of the options to be checked, yet disabled.

Is there a built-in visual style, or would I need custom CSS? This doesn't seem to work:

<div class="btn-group" data-toggle="buttons">

  <label class="btn btn-primary  disabled">
    <input class="form-control" name="beard" value="fluffy" disabled="" type="checkbox"> Fluffy
  </label>

  <label class="btn btn-primary  disabled">
    <input class="form-control" name="beard" value="scraggly" disabled="" type="checkbox"> Scraggly
  </label>

  <label class="btn btn-primary  active disabled">
    <input class="form-control" name="beard" value="pointy" disabled="" checked="" type="checkbox"> Pointy
  </label>

</div>

Functionally, I suppose the last option is checked, but visually it appears no differently than the disabled options.

Must avoid using any additional JS.