[libxml++] on_characters not being callled

[John Harpour <john harpour com>]

I am moving a project component from the C expat xml parser too libxmlc++.

Essentially I am looking to override the do_characters method in my own 
Parser object to extract the values of the elements (pretty much like 
you would do in expat).

Looking at the sax_parser example it appears the on_characters function 
is not being called during the document parsing?

I am probably missing something obvious here.....but understanding why 
would be helpful.

Thanks
John