Yii how to include ssh2 library

Question

I am Newbie in Yii and i am trying to include the library ssh2 in Yii, I made:

set_include_path(get_include_path().PATH_SEPARATOR.'/home/local/php/');
include('Net/SSH2.php');
$ip = "192.168.199.17";
$ssh = new Net_SSH2($ip);

It gives:

Error 500
include(Math_BigInteger.php): failed to open stream: No existe el fichero o el directorio


Notice: Use of undefined constant NET_SSH2_DISCONNECT_BY_APPLICATION - assumed 'NET_SSH2_DISCONNECT_BY_APPLICATION' in /home/local/php/Net/SSH2.php on line 2937

But it works propetly out of yii, I mean as a simple php file in htdocs. So I guess I am not including them in Yii....

Thanks all!