setting a Value on TwinColSelect (right column)

Hello,

im programming an internal mailsystem with vaadin 6.8.1.

Everthing works fine i have just one problem.

I initialize a form with a “message” - BeanItem:

    BeanItem<Message> newmessage = new BeanItem<Message>(message);                
    MessageFieldFactory factory = new MessageFieldFactory();        
    setFormFieldFactory(factory);        
    super.setItemDataSource(newmessage);    

If you answer a mail the form is initialized with a BeanItem which contains already the sender as recipient.
The recipients are a Set. Then it is initialized like that:

     Message message = new Message();
     Set<employee> setemp = new HashSet<employee>();
     setemp.add(oldmessage.getRecipient());
     message.setRecipient(setemp);

//and put the message in a BeanItem like above…

It works fine and the message will be sent to the right person, but the TwinColSelect wont display the value in the right coloumn.
It does with the value of the message in the textfield. But not with the set of employees.

Hope somebody can lead me into the right direction.

Thanks in advance