ADF Faces: sorting in af:table does'n work after migration fr. EA11 to EA13

Question

I have a JSF JSP with an <af:table> component (EA11). Sorting of columns in this table works fine with this code:
<af:column>
<f:facet name="header">
<af:sortableHeader text="Name" property="Name"/>
</f:facet>
<af:outputText value="#{item.Name}"/>
</af:column>
Then i migrate to EA13 and changed the code to:
<af:column sortProperty="Name" sortable="true">
<f:facet name="header">
<h:outputText value="Name"/>
</f:facet>
<af:outputText value="#{item.Name}"/>
</af:column>
=> the column headers are rendered as sortable, but sorting of columns does not work!
The bean property, the value attribute of the table is bound to, extends oracle.adf.view.faces.model.CollectionModel.
I will give you a hint: documentation to <af:column> and <af:table> always describes how to implement sorting with <af:sortableHeader>.

Answer 1

I use my own Implementation of CollectionModel. It extends oracle.adf.view.faces.model.CollectionModel.
The setSortCriteria method is called correctly. Even the sorting is done correctly. I just don't see it in my page. If I click on a column header to sort the column my cursor transforms to an hourglass, and that's it. Then I click on another button which makes the page render again, and suddenly the table is sorted according to the column I clicked before.