div.RadComboBox_Default .rcbArrowCell, div.RadComboBox_Default .rcbFocused .rcbArrowCell  {
    background-image: url(../images/NPAComboBoxSprite-IE8.png) !important;
    background-position: 0 0;
    width: 17px !important;
}
div.RadComboBox_Default .rcbHovered .rcbArrowCellRight {
    background-position: -17px 0 !important;
}