Facebook emoticon in comment

Now in facebook, you can comment with add an emoticon. It's start from today 12 october 2012, i know when i open facebook, because when i see my comments with emoticon *alpha, it's converted from alpha to image. How to do that?, simply, like in the chatting box in facebook, when you write a comment just add :D :v or -_- or anything. But you can't use the custom emoticon like: [[facebook]], [[zuck]] or [[google]]. Look my screenshot below: