Next time you reply to a message you'll see a new box on the left. You can either select a new smilie from the drop down menu (a preview of the smilie will appear in the box then you click on it to add it to your reply) or click on View All Smilies then choose which one you want by clicking on it.
Have a go now. ;D
These new smilies also appear in the Quick Reply box too. #afro#