UI version 1.5 slider( "moveTo", value, index ) function doesn't work?

UI version 1.5 slider( "moveTo", value, index ) function doesn't work?


I tried to move the slider programmably but the slider( "moveTo",
value, index ) function doesn't seem to work at all. this is my code:
//add sliders to div
$("#slider").slider({
    min: 0,
    max: 15,
    steps: 15,
    range: true,
    handles: [{start:2, min:0, max:14, id:"sliderFrom"}, {start:4, min:1,
max:15, id:"sliderTo"}],
    change: function(e,ui) { console.log("value: " + ui.value + ",
range:" + ui.range); }
});
$("#slider").slider("moveto", 8, 1); // trying to move the 2nd slider
(index=1) to value 8.
Am I doing something wrong here? Please help! Thanks in advance!