My first custom converter: why not call?

I wrote my first JSF (1.2) converter. I declared it in faces-config.xml ( converter-idand converter-class), wrote a Java class that implements the getAsObject and getAsString methods. Then I put the converter on the page as follows:

    <ice:selectInputDate id="ctldatanascita" 
                  value="#{beanrichiestaabilitazione.datanascita}"
          renderAsPopup="true">
      <f:converter converterId="cisConverterDate" />
    </ice:selectInputDate>

The class istantiated, but Converter interface methods are never called. What am I missing?