How do I manipulate layer text when using ember font-awesome?

I'm using the official ember font-awesome library and I'm trying to add some text to an icon with the following code:

  <span class="fa-layers fa-lg">
    <FaIcon @icon="circle" @size="3x" />
    <span class="fa-layers-text  fa-inverse" data-fa-transform="shrink-8">
      27
    </span>
  </span>

From what I can see on the documentation examples that should work but no value in the data-fa-transform attribute produces any change.

Is there a different method I need to use because FA now uses SVGs?