Passing data back and forth to overlays

I'm having a tough time trying to incorporate a jquery/ajax tree for adding nodes to a geneology tree, using the code found here:

I've already dug through all the tutorials, including the ajax and jquery ones (great tutorials by the way). I have many questions, but here is one that I am currently stuck on:

Is there a way to send and receive data from a overlay form that isn't called using "class=OverlayTrigger" ? The code I'm using is calling an overlay using something like:

$('.'+class_name+'. span.add_action').live('click', function() {... call overlay ... });
The code registers a click event on a <span> object and brings up my overlay form (with minor issues), but I'm unsure of how to deal with sending data to that overlay form and receiving it back; without doing all of this through Xenforo.register and the <a href ... class=OverlayTrigger>. I want to be able to send some default information (like the name, age date, etc), from the list (<li>) element that the <span class=add_action> is attached to, and have them modify it, and then send it back to update the geneology tree.

The reason why I'm trying to approach this problem this way, is that I would rather not have to re-write all of the code associated with drawing the tree. I'm not even sure if I'm capable of doing that.
Ok, I've found out that I can pass data to the eventhandler in .on():

.. which will allow me to pass data to a handler. I guess I can pass that data to whatever handler that calls Xenforo.ajax. won't know until i test it tonight. what about the info going the other way?