在myeclipse里用wsdl构建Web Service出现错误

Question

WSDL文件部分内容如下
<?xml version="1.0" encoding="UTF-8"?>
<wsdl:definitions targetNamespace="urn:taskbuild.server.ws.epm" xmlns:impl="urn:taskbuild.server.ws.epm"  xmlns:apachesoap="http://xml.apache.org/xml-soap" xmlns:wsdlsoap="http://schemas.xmlsoap.org/wsdl/soap/" xmlns:soapenc="http://schemas.xmlsoap.org/soap/encoding/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:wsdl="http://schemas.xmlsoap.org/wsdl/">     <wsdl:types>
     </wsdl:types>
       
   <wsdl:message name="methodRequest">
      <wsdl:part name="msgParam" type="soapenc:string"/>       
   </wsdl:message>
eclipse弹出的错误提示如下
Schema descriptor {http://schemas.xmlsoap.org/soap/encoding/" }string in message part "msgParam" is not defined and could not be bound to Java. Perhaps the schema descriptor {http://schemas.xmlsoap.org/soap/encoding/" }string is not defined int the schema imported/included in the WSDL. you can either add such imports/includes or run wsimport and provide the schema location using -b switch.假如我把type="soapenc:string改为type="xsd:string的话就会没问题。为什么呢？
还有能如何解决呢？还是想用soapenc