you could easily add any labels or images using facets for the controls.
Yes, that would be possible... But I just thought that the component should come with a something on the next and previous buttons as well, since it has images on the other 4 buttons...
As you could see fast scrolling controls has step=1 by default. So them works the same as next prev controls. So thats why default design contains text labels only for the buttons you see.