Problems consuming Webservice, returning NULL everytime

Hello everybody, I'm trying to do a webservice with php5 SOAP, after done the class, generated the wsdl file and coded the client, when I try to run it on a browser the function I call always returns NULL, why that? I tryed first to do a simple addition, but as this isn't working, I tryed just to return one of the parameters of the function but it isn't working either, what should I do? I'm using a generator to obtain the wsdl file

This is my code:
class with generator (example.php)

<?php


/**
 * this is a class
 */
class Foo {
  /** The add function
   * @param int $x
   * @param int $y
   * @return int
   */
  function Add($x,$y) {
        if($x == null)
                return 0;
        elseif($y == null)
                return 1;
        else return 2;
  }
}

include '../WSDL_Gen.php';
$wsdl = new WSDL_Gen('Foo', 'http://172.16.0.147:81/~jgonzal/WebserviceTest/wsdlTools/WSDL/Foo/Foo.php', 'http://172.16.0.147:81/~jgonzal/WebserviceTest/wsdlTools/WSDL/Foo/');
print $wsdl->toXML();
?>

PHP:

The Foo class is like this, as you will see it is equals as the class into de wsdl generator file (Foo.php)

<?php

/**
 * this is a class
 */
class Foo {
  /** The add function
   * @param int $x
   * @param int $y
   * @return int
   */
  function Add($x,$y) {
        if($x == null)
                return 0;
        elseif($y == null)
                return 1;
        else return 2;
  }
}
?>

PHP:

This is the autogenerated wsdl file (wsdlFoo.wsdl):

<?xml version="1.0" ?>
 <definitions xmlns="http://schemas.xmlsoap.org/wsdl/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:tns="http://172.16.0.147:81/~jgonzal/WebserviceTest/wsdlTools/WSDL/Foo/" xmlns:soap-env="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" targetNamespace="http://172.16.0.147:81/~jgonzal/WebserviceTest/wsdlTools/WSDL/Foo/">
 <types>
 <xsd:schema>
 <xsd:complexType name="array">
 <xsd:complexContent>
 <xsd:restriction base="soapenc:array">
  <xsd:attribute ref="soapenc:arrayType" arrayType="tns:mixed[]" />
  </xsd:restriction>
  </xsd:complexContent>
  </xsd:complexType>
 <complexType name="mixed">
 <all>
  <element name="varString" type="xsd:string" />
  <element name="varInt" type="xsd:int" />
  <element name="varFloat" type="xsd:float" />
  <element name="varArray" type="tns:array" />
  </all>
  </complexType>
  </xsd:schema>
  </types>
 <message name="AddInput">
  <part name="x" type="xsd:int" />
  <part name="y" type="xsd:int" />
  </message>
 <message name="AddOutput">
  <part name="return" type="xsd:int" />
  </message>
 <portType name="FooPortType">
 <operation name="Add">
  <input message="tns:AddInput" />
  <output message="tns:AddOutput" />
  </operation>
  </portType>
 <binding name="FooBinding" type="tns:FooPortType">
  <soap-env:binding xmlns="http://schemas.xmlsoap.org/wsdl/soap/" style="rpc" transport="http://schemas.xmlsoap.org/soap/http" />
 <operation xmlns:default="http://schemas.xmlsoap.org/wsdl/soap/" name="Add">
 <input xmlns:default="http://schemas.xmlsoap.org/wsdl/soap/">
  <soap-env:body xmlns="http://schemas.xmlsoap.org/wsdl/soap/" use="encoded" encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
  </input>
 <output xmlns:default="http://schemas.xmlsoap.org/wsdl/soap/">
  <soap-env:body xmlns="http://schemas.xmlsoap.org/wsdl/soap/" use="encoded" encodingStyle="http://schemas.xmlsoap.org/soap/encoding/" />
  </output>
  </operation>
  </binding>
 <service name="FooService">
 <port xmlns:default="http://schemas.xmlsoap.org/wsdl/soap/" name="FooPort" binding="tns:FooBinding">
  <soap-env:address xmlns="http://schemas.xmlsoap.org/wsdl/soap/" location="http://172.16.0.147:81/~jgonzal/WebserviceTest/wsdlTools/WSDL/Foo/Foo.php" />
  </port>
  </service>
</definitions>

HTML:

This is my client code (clienteFoo.php)

<?php
  $soap = new SoapClient('wsdlFoo.wsdl');
  try {
    var_dump($soap->__getFunctions());
    $result = $soap->Add(47, 11);
    //if( $result != null || $result != '')
        echo "Variable1:";
        var_dump($result);
        echo "Variable2:";
        echo "<h1>47 + 11 = $result.</h1>";
    //else
//      echo "No se hizo la adicion";
  } catch (SoapFault $e) {
    echo "Error: {$e->faultstring}";
  }
?>

PHP:

Output in browser:

array(1) { [0]=> string(23) "int Add(int $x, int $y)" } Variable1:NULL Variable2:
47 + 11 = .