Include a third party library using namespaces, dependencies
It is indeed possible with xautoload.

Here is some explanation what initially went wrong:
https://gist.github.com/4018045

As a general guide:

function hook_libraries_info() {
  return array(
    'Taleo' =&gt; array(
      'name' =&gt; 'Taleo PHP Library',
      'xautoload' =&gt; function($api) {
        // $api already knows the library path.
        // 'src' is relative to that.
        $api-&gt;namespaceRoot('Taleo', 'src');
      },
    ),
  );
}


The $api object is explained here:
http://drupalcode.org/project/xautoload.git/blob/refs/heads/7.x-2.x:/lib/InjectedAPI/hookXautoload.php