Spring convert error - bean implements same interface as constructor arguments

Question

I have an error which I've never seen before in Spring(I'm newbie:D). I have 3 classes(MainDao, DaoV1, DaoV2) which implement same interface(Repo) MainDao has two constructor arguments which are DaoV1 and DaoV2. The creation of DaoV1 and DaoV2 is totally fine, but when I add MainDao bean in xml, I get the error below! What is the problem?

Error message:

org.springframework.beans.factory.access.BootstrapException: 
Unable to initialize group definition. Group resource name 
[classpath*:beanRefContext_SomeService.xml], factory key 
[applicationContext_SomeService]; nested exception is
 org.springframework.beans.factory.BeanCreationException:
 Error creating bean with name 'applicationContext_SomeService'
 defined in URL [file:/opt/ibm/AppSrv70_1/installedApps/cell01/SomeService.ear/SomeServiceWebV2.war/WEB-INF/classes/beanRefContext_SomeService.xml]: Instantiation of bean failed; 
nested exception is org.springframework.beans.BeanInstantiationException: 
Could not instantiate bean class [org.springframework.context.support.ClassPathXmlApplicationContext]: 
Constructor threw exception; nested exception 
is org.springframework.beans.factory.UnsatisfiedDependencyException: 
Error creating bean with name 'mainDao' defined in class path resource 
[SomeServiceDaoEjb-context.xml]: Unsatisfied dependency expressed through
 constructor argument with index 0 of type [com.example.dao.DaoV1]: Could 
not convert constructor argument value of type [$Proxy197] to required type 
[com.example.dao.DaoV2]: Failed to convert value of type '$Proxy197 implementing com.example.spi.Repo,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised' 
to required type 'com.example.dao.DaoV1'; nested exception is java.lang.IllegalStateException:
 Cannot convert value of type [$Proxy197 implementing com.example.spi.Repo,org.springframework.aop.SpringProxy,org.springframework.aop.framework.Advised]
 to required type [com.example.dao.DaoV1]: no matching editors or conversion strategy found

Repo.class

public interface Repo {
  Item retrieve(Integer var1, Integer var2);
}

DaoV1.class

public class DaoV1 implements Repo {
  final ClassA arg1;
  private ClassB arg2;

  public DaoV1(ClassA arg1, ClassB arg2) {
    this.arg1 = arg1;
    this.arg2 = arg2;
  }

  public Item retrieve(Integer var1, Integer var2) {
    // arg.get() ....
  }
}

DaoV2.class

public class DaoV2 implements Repo {
  private SampleService service;

  public DaoV2(SampleService service) {
    this.service = service;
  }

  public Item retrieve(Integer var1, Integer var2) {
    // service.get() ....
  }
}

MainDao.class

public class MainDao implements Repo {
  private DaoV1 v1;
  private DaoV2 v2;

  public MainDao(DaoV1 v1, DaoV2 v2) {
    this.v1 = v1;
    this.v2 = v2;
  }

  public Item retrieve(Integer var1, Integer var2) {
    //
  }
}

Beans

<bean id="v1" class="com.example.dao.DaoV1">
  <constructor-arg ref="classAParam" />
  <constructor-arg ref="classBParam" />
</bean>

<bean id="v2" class="com.example.dao.DaoV2">
  <constructor-arg ref="service" />
</bean>

<bean id="maindao" class="com.example.dao.MainDao">
  <constructor-arg ref="v1" />
  <constructor-arg ref="v2" />
</bean>