[xml] Using psvi field as a second pointer in addition to _private

[Brian Smith <brian dbsoft org>]

I am writing an application which needs two separate things connected by 
an libxml2 node...

Is it possible to use the psvi field to do that if I avoid using schema 
validation?  If so what must I avoid doing?

Or is there another easy way to store two pointers on an XML node?

Basically the XML tree is storing a hierarchical user interface layout, 
which is represented by a tree view widget in the user interface.  The 
handle to the tree node is currently stored in the _private field and I 
need another field to store the widget handle of the preview window. 
So when changes are made to the xml node the preview window can be 
updated along with the node in the tree view.

Any ideas?

Thanks,
Brian