JStree AJAX lazy loading and submitting of selected nodes to server

Sometimes your need to work with trees.
After some time of research I could find 2 implementations of javascript trees: jsTree (http://www.jstree.com/) and Dynatree (http://code.google.com/p/dynatree/).

I could only try jsTree because of limited time.
So, here are my requirements:
1) lazy loading of selected nodes. It's because tree size can be quite big. And store all the tree is unnecessary.
2) one can choose any number of nodes and submit selected nodes of the tree to server.