Facebook is different.. I don't have a good reason why as the actual reason is outdated.. but use {JFBCLogin}.. it will work. However, we have an easytag for the login button itself that can let you include whichever provider buttons you want:
{SCLogin providers=twitter,facebook,google}
That will show those 3 login buttons, in that order.
I hope that helps, but if you need anything else, just let us know.
Thanks,
Alex