Use the change event of the dataSource.
(e.items.length > 0 && e.action ==
// your code to look for the new node to expand here
Then expand your root node through the uid attribute (as the treeview has it's own findByUid method).
t = $(
When it expands and is going to add the children nodes it will fire the change event, if you need to keep opening more nodes you will have to do the same within the change event (look for the node and expand it).