It's doable, though it requires a bit more than using the list-style properties in CSS:
Here's what i was able to put together that worked reasonably well for me. You'll likely have to tinker with the numbers a bit to get it exactly right for you, but give this a shot:
li{
height:25px;
list-style:none;
padding-left:35px;
padding-top:10px;
padding-bottom:10px;
background:url(http://dkpfiles.com/theresidual/files/icon_neutral.png) no-repeat left center;
vertical-align:middle;
}