I don't know then. For eevee, you put : 7 : without the spaces. And it won't appear until you actually post. Are you trying to use the trozei ones? Try taking out the t in the emoticon and see what happens.
Man, how many stalkers do I have? :P Anyways, I can't find Darkrai. You might want to look yourself. Simply click Go Advanced. Then click the Smilie icon. Scroll to the bottom of that short list and click the option there to see a full list. :D