Indexes for all items of Tree

Hi,
How can I get indexes for all items of Tree?
Is absent A11 and A12 (4: [5,6] ).
var tree = { 
        0: [1, 2, 3], 
        1: [4], 
        2: [7], 
        3: [8], 
        4: [5,6] 
         
    } 
    var obj = new AW.UI.Tree; 
    obj.setItemText(["", "A", "B", "C", "A1", "A11", "A12", "B1", "C1"]); 
    obj.setViewCount(function(i){return tree[i] ? tree[i].length : 0}); 
    obj.setViewIndices(function(i){return tree[i]}); 
    document.write(obj); 

    for(var x=0; x<=tree[0].length; x++)
{ 
for(var y=1; y<=tree[x].length; y++)
 { 
  
indItem=tree[x][y-1]
alert(obj.getItemText(indItem)+" "+ indItem);

}
}  Thanks.