Viewlet - Get n level Tree Structure Nodes

Hi,

Can any body let me know, how to achieve Tree Structure in viewlet for n level of tree hierarchy?
I looked into the WorkItemQueryChooser, but not getting for n number of tree depth.
There I could only get upto two level tree hierarchy. There "jazz.ui.ModeledTree" and "jazz.ui.tree.IconItem" are being used. But unable to get any example for these any where.
Unable to understand the api also for these.
Can anybody let me know how to achieve n level of tree hierarchy in viewlet?
Its urgent for me.