Problems with picklist

[shadlock]

Hi all,

  i'm using Seam 2.2.2 and richfaces 3.3.1, i have a problem with picklist it's my code

import java.util.HashMap;
import java.util.List;


import javax.faces.component.UIComponent;
import javax.faces.convert.Converter;
import com.hp.gecpso.entity.asset.ASTCluster;
import javax.faces.context.FacesContext;

public class ClusterConverter implements Converter {
  //converter uses a HashMap for switching from selectItems to your objects  
    private HashMap <String, ASTCluster> map;  


  public  ClusterConverter(List<ASTCluster> objekts) {  
            map=new HashMap<String, ASTCluster>();  
            for(ASTCluster o : objekts){  
                    map.put(Integer.toString(o.getId()), o);  
            }  
    }  


    public ClusterConverter() {
  // TODO Auto-generated constructor stub
  }


  public Object getAsObject(FacesContext arg0, UIComponent arg1, String string) {  
            return map.get(string);  
    }  


    public String getAsString(FacesContext arg0, UIComponent arg1, Object obj) {  
            if(obj instanceof ASTCluster)   
                    return Integer.toString(((ASTCluster)obj).getId());  
            return null;  
    }






}

@In(create=true, required=false)
  @Out(required=true,scope=ScopeType.PAGE)
  //private List<SelectItem> leftPickList ;  
  private List<SelectItem> leftPickList ;  

  @In(create=true, required=false)
  @Out(required=true,scope=ScopeType.PAGE)
  private List<ASTCluster> pickListResult ;  

.............

public void addRemoveCluster(){


  @SuppressWarnings("static-access")
  List <ASTCluster> listaCluster= DBManagedServer.getInstance().getClusterSession().getAllcluster();
  pickListResult=assetSelected.getClusters();


  for (Iterator<ASTCluster> iterator = listaCluster.iterator(); iterator.hasNext();) {
  ASTCluster astCluster = (ASTCluster) iterator.next();
  SelectItem a= new SelectItem(astCluster.getId(), astCluster.getClusterName());
  leftPickList.add(a);
  }
  }

The page

<!DOCTYPE composition PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<ui:composition xmlns="http://www.w3.org/1999/xhtml"
    xmlns:s="http://jboss.com/products/seam/taglib"
    xmlns:ui="http://java.sun.com/jsf/facelets"
    xmlns:f="http://java.sun.com/jsf/core"
    xmlns:h="http://java.sun.com/jsf/html"
    xmlns:a4j="http://richfaces.org/a4j"
    xmlns:rich="http://richfaces.org/rich"
                xmlns:c="http://java.sun.com/jsp/jstl/core">




  <a4j:outputPanel ajaxRendered="true" >
  <a4j:form  id="assetaddcluster" ajaxSubmit="true">  

    <rich:simpleTogglePanel label="Asset Search Filter" switchType="ajax" width="100%"> 
      <h:panelGrid columns="8">
      <h:outputLabel value="#{messages['clusters.nome']}" />
            <h:inputText value="#{clusterFilter.nomeCluster}" />
           
            <h:outputLabel value="#{messages['clusters.cluster']}" />
      <h:selectOneMenu  value="#{clusterFilter.tipoCluster}" >
        <s:selectItems value="#{tipoCluster}" var="obj" label="#{obj}" itemValue="#{obj}" noSelectionLabel="Please select..." />  
         </h:selectOneMenu>
      
      </h:panelGrid>
      <div class="actionButtons">
  <a4j:commandButton value="Search" action="#{ASTAssetController.filterCluster()}" reRender="" requestDelay="500"/>
    <a4j:commandButton value="Reset" action="#{ASTAssetController.clearFilterCluster()}" reRender=""/>
              </div>
      </rich:simpleTogglePanel>


  <rich:pickList  value="#{pickListResult}" converter="#{converterAsset}">
     <f:selectItems value="#{leftPickList}"/>
        </rich:pickList>
        
  <div class="actionButtons">
  <a4j:commandButton value="Save" action="#{ASTAssetController.saveCluster()}"  oncomplete="Richfaces.hideModalPanel('addClusterOnAsset')" reRender="">
  <a4j:support event="onclick" onsubmit="if (!confirm('#{messages['sitSiteConfirmInsert']}')){return false;}" />
  </a4j:commandButton>
  </div>

  </a4j:form>
     <rich:messages id="errorChecksaddcluster" globalOnly="true" styleClass="cntError" style="font-size:12px;width:100%;"/>
    </a4j:outputPanel>
</ui:composition>

I can load the value on the left side of the of the picklist but as soon as i use the search button or the save button i get an error

javax.servlet.ServletException: ValueBinding for UISelectMany must be of type List or Array

  at javax.faces.webapp.FacesServlet.service(FacesServlet.java:277)

  at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)

  at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)

  at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:83)

  at org.jboss.seam.web.IdentityFilter.doFilter(IdentityFilter.java:40)

  at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)

  at org.jboss.seam.web.MultipartFilter.doFilter(MultipartFilter.java:90)

  at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)

  at org.jboss.seam.web.ExceptionFilter.doFilter(ExceptionFilter.java:64)

  at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)

  at org.jboss.seam.web.RedirectFilter.doFilter(RedirectFilter.java:45)

  at org.jboss.seam.servlet.SeamFilter$FilterChainImpl.doFilter(SeamFilter.java:69)

  at org.ajax4jsf.webapp.BaseXMLFilter.doXmlFilter(BaseXMLFilter.java:178)

  at org.ajax4jsf.webapp.BaseFilter.handleRequest(BaseFilter.java:295)

I can't find a solution ... someone can help?