How to get item caption value in krpano combobox plugin?

Does anyone know how to get <item> caption value in krpano combobox plugin?

example.: I have plugin[combo] and I have subnode name="item2". I wont to get text value caption of this subnode. I've tried get(plugin[combo].item[item2].caption) but isn't work

<plugin name="combo"
url="combobox.swf"
alturl="combobox.js"
align="leftbottom" x="10" y="10"
onloaded="fillbox();"
/>

<action name="fillbox">
addIdItem(item1, 'Item 1', trace(Item 1 clicked) );
addIdItem(item2, 'Item 2', trace(Item 2 clicked) );
addIdItem(item3, 'Item 3', trace(Item 3 clicked) );
...
</action>

Thanks and best regards
Michael

It is not working when I add items dynamically to combobox plugin