如何在Objective-C中发出SOAP WSDL请求?

我有一个WSDL脚本,其格式如下

<definitions name="ProcessData" targetNamespace="urn:ProcessData">

<message name="CreateAccount">
<part name="firstName" type="xsd:string"/>
<part name="lastName" type="xsd:string"/>
<part name="password" type="xsd:string"/>
<part name="emailAddress" type="xsd:string"/>
<part name="sendEmail" type="xsd:string"/>
<part name="key" type="xsd:string"/>
</message>

<message name="CreateAccountResponse">
<part name="result" type="xsd:string"/>
</message>
<definitions>

如何在Objective-C中提出SOAP WSDL请求并得到响应?

谢谢