null param in rendered action

[jmchiaradia]

Hello,

I have a problem with a rendered action param.
I have a datatable that shows some objects properties and should render an edit link if this object is editable.
Here is the code:

<rich:dataTable
     value="#{beanList.objList}"
     var="_obj">
     <rich:column>
          <f:facet name="header">Some Property</f:facet>
          <h:outputText value="#{_obj.property}" />
     </rich:column>
     <rich:column>
          <f:facet name="header">Actions</f:facet>
          <a4j:commandLink 
               value="edit" 
               rendered="#{checkBean.isEditable(_obj)}"
               action="#{useCaseManager.editObject(_obj)}" />
     </rich:column>
</rich:dataTable>

The problem is that

checkBean.isEditable(_obj)

is receiving a null value instead of object.

The object is not null since

_obj.property

is rendered ok.

Could any one help me?

Thanks,
Chiara