[SOLVED] Images in widgets

In my http:\\www.bvision.nl blog I changed the colors to the colors used in the Montezuma theme. But how do I change the boxes next to the items in the sidebar to the used images in that theme? I tried in the widgetoptions: list-style-image: url('http://www.bvision.nl/wp-content/themes/atahualpa3/images/dart.gif');
that doesn't work. I tried the code in w3 and there it works well.