xsd:Import doesn't work in WSDL?

Question

Hi,

When put below wsdl into my VS2010 project I got a "Type 'urn:listing3:Phone' is not declared." error. Looks like the xsd:import doesn't work, why?

<?xml version="1.0" ?>
<wsdl:definitions targetNamespace="urn:listing2"
                  xmlns:tns="urn:listing2"
                  xmlns:listing3="urn:listing3"
                  xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/"
                  xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
  <wsdl:types>
    <xsd:schema targetNamespace="urn:listing3"
                xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
      <xsd:import namespace="http://www.w3.org/2001/XMLSchema"/&gt;
      <xsd:complexType name="Phone">
        <xsd:sequence>
          <xsd:element name="areaCode" type="xsd:int"/>
          <xsd:element name="exchange" type="xsd:int"/>
          <xsd:element name="number" type="xsd:int"/>
        </xsd:sequence>
      </xsd:complexType>
    </xsd:schema>
    <xsd:schema targetNamespace="urn:listing2"
                xmlns:listing3="urn:listing3"
                xmlns:xsd="http://www.w3.org/2001/XMLSchema"&gt;
      <xsd:import namespace="urn:listing3"/>
      <xsd:import namespace="http://www.w3.org/2001/XMLSchema"/&gt;
      <xsd:complexType name="Address">
        <xsd:sequence>
          <xsd:element name="streetNum" type="xsd:int"/>
          <xsd:element name="streetName" type="xsd:string"/>
          <xsd:element name="city" type="xsd:string"/>
          <xsd:element name="state" type="xsd:string"/>
          <xsd:element name="phone" type="listing3:Phone"/>
        </xsd:sequence>
      </xsd:complexType>
    </xsd:schema>
  </wsdl:types>

  <wsdl:message name="GetAddressRequest">
    <wsdl:part name="name" type="xsd:string"/>
  </wsdl:message>
  <wsdl:message name="GetAddressResponse">
    <wsdl:part name="address" type="tns:Address"/>
  </wsdl:message>
  <wsdl:message name="GetPhoneRequest">
    <wsdl:part name="name" type="xsd:string"/>
  </wsdl:message>
  <wsdl:message name="GetPhoneResponse">
    <wsdl:part name="phone" type="listing3:Phone"/>
  </wsdl:message>

  <wsdl:portType name="AddressBook">
    <wsdl:operation name="getAddress">
      <wsdl:input message="tns:GetAddressRequest"/>
      <wsdl:output message="tns:GetAddressResponse"/>
    </wsdl:operation>
    <wsdl:operation name="getPhone">
      <wsdl:input message="tns:GetPhoneRequest"/>
      <wsdl:output message="tns:GetPhoneResponse"/>
    </wsdl:operation>
  </wsdl:portType>
</wsdl:definitions>

The error is, type Phone is declared in namespace listing3, the namespace is also imported in namespace listing2 using <xsd:import>, but type Phone cannot be referenced in listing2. The error message is "Type 'urn:listing3:Phone' is not declared".

Update:
The wsdl was generated automatically by VS2010 when adding the Java web service as a web reference. The wsdl I posted here actually is not the real wsdl but a fake one for security reason. But the structure of both wsdl and the error messages are almost same.