There are placeholders checked in for "add method", "add listener", "remove method", "remove listener". The simplest way to create the icons is by adding a letter (M or L) on top of the existing icon-trash.gif and icon-plus.gif, but maybe there are other ideas.
http://www.iconlet.com/info/16599_newlistener_wiz_75x66 could be used for "listener"
Ahmed.
