为什么Spring不能将实现类型的代理转换为该类型？

Question

我使用Spring Security 3.1.4运行Spring 3.2.4。当我尝试将我的应用程序部署到WebLogic时，我收到错误。根错误似乎是：

...nested exception is java.lang.IllegalStateException: 
Cannot convert value of type [
com.sun.proxy.$Proxy445 implementing 
 xxx.SecurityAuditorService,
 org.springframework.aop.SpringProxy,
 org.springframework.aop.framework.Advised
] 
to required type [
 xxx.SecurityAuditorService] 
for property 'securityAuditorService': 
no matching editors or conversion strategy found
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:329)

以下是我不理解的内容...为什么不能将实现SecurityAuditorService的代理转换为所需类型的SecurityAuditorService？

编辑（配置信息）： 安全通用：

<bean id="securityAuditorService" class="xxx.SecurityAuditorServiceImpl">
   <!-- properties omitted -->
</bean>

SecurityAuditorServiceImpl.java

public class SecurityAuditorServiceImpl implements SecurityAuditorService{
   // internals omitted
}