Hello!

I think it would be quite useful to provide, for the async version of the TreeView, the ability to associate a Callback for a succesful async (AJAX) request which loads data into the tree. This is different from the "toggle" event, as it's called also at the initial data load and it doesn't get called when closing nodes.

I patched jquery.treeview.async.js this way (diff -U is attached). It works on my system, however it might not be the ideal way. ;)