List Shuttle - help!

<rich:listShuttle sourceValue="#{obraBean.listaFase}" var="fase"
						targetValue="#{obraBean.faseSelecionada}"
						converter="FaseConverter">
						<rich:column>
							<h:outputText value="#{fase.descricao}" />
						</rich:column>
					</rich:listShuttle>

public Object getAsObject(FacesContext context, UIComponent component, String value)
			throws ConverterException {
		
		if(value != null){
			return this.getAttributesFrom(component).get(value);
		}
		
		return null;
	}

	public String getAsString(FacesContext context, UIComponent component, Object value)
			throws ConverterException {
		
		if(value != null && !"".equals(value)){
			
			Fase f = (Fase) value;
			
			this.addAttribute(component, f);
			
			Integer codigo = f.getId();
			
			if(codigo != null){
				return String.valueOf(codigo);
			}
		}
		
		return (String)value;
	}
	
	 protected void addAttribute(UIComponent component, Fase o) {  
         String key = o.getId().toString(); 
         this.getAttributesFrom(component).put(key, o);  
     }  
   
     protected Map<String, Object> getAttributesFrom(UIComponent component) {  
         return component.getAttributes();  
     }

<converter>
		<converter-id>FaseConverter</converter-id>
		<converter-class>util.FaseConverter</converter-class>
	</converter>

private List<Fase> faseSelecionada = new ArrayList<Fase>();

//get e set

@SuppressWarnings("unused")
	private List<Fase> listaFase = new ArrayList<Fase>();

@SuppressWarnings("unchecked")
	public List<Fase> getListaFase(){

		Session session = HibernateUtil.getSession();
		
		try {
			Criteria criteria = session.createCriteria(Fase.class);
			criteria.add(Restrictions.eq("cancelado", "N"));
			return criteria.list();
		} catch (Exception e) {
		} finally{
			session.close();
		}
		
		return null;
	}

public void setListaFase(List<Fase> listaFase) {
		this.listaFase = listaFase;
	}