[xwt-users] How to get a sub-box in Lithium?

This is using Lithium...
If a template contains a another template, how do I get the handle to a 
sub-box (field)?

ex: [top]

...
<cardpane>
<subbox id="subbox" />
</cardpane>

[subbox.xwt]
...
<box>
<box id="subbox_wanted" ...>
...

 From in [top], how I to get a handle to id=subbox_wanted?
Note I may not know how many box levels inside subbox the subbox_wanted 
box is.
I would also be happy to just call a function (trap) defined inside 
[subbox.xwt] that could then have local access (thisbox, etc.).

If this was at a top level (all boxes in [top]), I would just use:
var name="subbox_wanted";
wantThis = thisbox["$" + name];

I have tried multiple things including:
$subbox_wanted.thisbox["$" + name]; // and related things

Thanks,

-Jeff

Jeff Buhrt
Achievement Focused Technology, Inc.
[email protected]
http://aftinc.net