If you will not be satisfied with XML::Simple or XML::Twig, you can try XML::Trivial - I have designed it with idea of exact parsing and keeping all what is in the origin document, namely CDATA sections.

Though XML::Trivial makes just read-only document tree structure, it could be easy to iterate parsed tree and print desired output, or, to hack XML::Trivial::Element::sr method, which serializes any element.