Creating plugin, please help on schema types

Hi,

I want to create a plugin that builds a PL/SQL package (WS-Client) out of a WSDL.
Let's say I use this WSDL: http://www.webservicex.net/geoipservice.asmx?WSDL
I want to generate the code to invoke GetGeoIP and parse the response.
Basically I need - more or less - the generate the request text as SoapUI does itself (request1).

I am kind of stuck on getting the Schema Types:
When I start from

public class Foo extends AbstractSoapUIAction<WsdlProject>
public void perform (WsdlProject target, Object param)

Then how do I get to the complexType element:

<s:element name="GetGeoIP">
<s:complexType>
<s:sequence>
<s:element minOccurs="0" maxOccurs="1" name="IPAddress" type="s:string"/>
</s:sequence>
</s:complexType>
</s:element>

I followed this path:

WsdlProject --> List<Interface> --> List<Operation> --> WsdlOperation --> .getBindingOperation() --> BindingOperation --> .getBindingInput() --> BindingInput

But then I am stuck...
How do I get to the message
<wsdl:message name="GetGeoIPSoapIn">
<wsdl:part name="parameters" element="tns:GetGeoIP"/>
</wsdl:message>

and the type as described above?

Thanks in advance!