JPAContainer, ComboBox and addNestedContainerPrope

Hi after read all posts about JPAContainer, FieldFactory and SingleSelectTranslator and lost days I found what didn't work on my code.

My Model is like (details are left outside):

public class Foo  {

  @NotNull
  @Size(max = 255)
  private String caption;

  @ManyToOne(fetch = FetchType.EAGER)
  private FooOwner fooOwner;

and

public class FooOwner {

  @Id//pay attention to this, I think it is the problem
  private String uniqueKey;

  @NotNull
  @Size(max = 255)
  private String caption;

Then I have a vaadin table of Foo instances where I need to shows also Foo caption, and Foo uniqueKey, so on the Foo container I added a nestedProperty,

fooContainer.addNestedContainerProperty("fooOwner.caption");
fooContainer.addNestedContainerProperty("fooOwner.uniqueKey");

and the table columns are:

table.setVisibleColumns(new String[] { "id", "fooOwner.caption", "fooOwner.uniqueKey", "start", "end", "caption" });

On the Foo vaadin Form I pass the EntityItem<Foo>,

fooForm.setItemDataSource(fooItem, Arrays.asList(new String[] { "start", "end", "caption", "fooOwner" })); 

I use the JPAContainer instance of FieldFactory and on the fooOwner I see a ComboBox (SingleSelectTranslator is used)

on update item all is ok, but if I create a new Item and save I got the following exception

java.lang.IllegalStateException: A null value was found in the chain of nested properties

If I remove the addNestedContainerProperty declaration and consequently the related table columns all works well.

Debugging the JPAContainerItem

public void commit() throws SourceException, InvalidValueException {
        if (!isWriteThrough()) {
            try {
                /*
                 * Commit all properties. The commit() operation will check if
                 * the property is read only and ignore it if that is the case.
                 */
                for (ItemProperty prop : propertyMap.values()) {
                    prop.commit();
                }

it gets the fooOwner properties and it seems to me as it confuse the fooOwner instence coming from comboBox with others fooOwner properties.

Could someone get me a rigth direction?
Does anyone did the same scenarious?

Regards

I found that adding a simple ValueChangeListener on the item like this,

this.item.addListener(new ValueChangeListener() {

      @Override
      public void valueChange(final ValueChangeEvent event) {
        System.out.println(event);
      }
    });

all nested item properties are added to the Item propertyMap so when I commit the form

public void commit() throws SourceException, InvalidValueException {
        if (!isWriteThrough()) {
            try {
                /*
                 * Commit all properties. The commit() operation will check if
                 * the property is read only and ignore it if that is the case.
                 */
                for (ItemProperty prop : propertyMap.values()) {
                    prop.commit();
                }
                modified = false;
                container.containerItemModified(this);
            } catch (Property.ConversionException e) {
                throw new InvalidValueException(e.getMessage());
            } catch (Property.ReadOnlyException e) {
                throw new SourceException(this, e);
            }
        }
    }

some properties (all unuseful nested properties) are null and

prop.commit();

will throws

Property.ConversionException

I don't know if this work as design or is a bug,
BTW I removed the listener, had the same functionality using a workaround.

Regards