Muk，你要到 app\code\core\Mage\Sales\etc 修改 wsdl.xml 和 wsi.xml 并为 sku 添加元素或根据您的要求提供任何您想要的东西.

Muk, you have to go to app\code\core\Mage\Sales\etc and modify wsdl.xml and wsi.xml and add the element for sku or whatever you want as per your requirement.

<element name="sku" type="xsd:string" minOccurs="0" /> //in wsdl.xml
<xsd:element name="sku" type="xsd:string" minOccurs="0" /> //wsi.xml

如果您不想修改核心文件，则必须覆盖它.

if you don't want to modify core file than you have to override it.