How to use libxml++ to write a file in c ++ xml

[carlo esposito <kevinstar libero it>]

Hi,
I'm using libxml + + library in C + +, and I have to write an xml file in which there is an inclusion of another xml file:

1 <? Xml version = "1.0"?>
2 <! DOCTYPE EXAMPLE SYSTEM "example.dtd" [
3 <! ENTITY xml "Extensible Markup Language">
4]>
5 <example>
6 &xml;
7 </ example>

I do not know which the method to use the library libxml++ to write the line 6: "& xml" ,I saw the classes Document, Element, ..... but I have not found any method to use to write code in my xml file line 6.
Can you help ?