more unordered list padding/margin cross-browser craziness

I just received this awesome help: Is there a way to extend background color of unordered list items to go behind bullets?

and then I was dealing with the text-indent property to again line up the wrapped text in this unordered list, but lo and behold it looks like IE and FF are handling the padding differently enough to really mess with the layout. Any solution?

Firefox (good)

_{(source: mbira.me)}

IE (bad)

_{(source: mbira.me)}

The css for the list:

.registerbox ul{

}

.registerbox ul li.light{
list-style-type:disc;
list-style-position:inside;
margin:2px 0px 2px -20px;
padding:2px 30px;
background-color:#FFFFB0;
text-indent:-12px;
}
.registerbox ul li.dark{
list-style-type:disc;
list-style-position:inside;
margin:2px 0px 2px -20px;
padding:0px 30px;
text-indent:-12px;
}

In order to fix this, I ended up making a png of the bullet and got rid of the default bullets.