h:commandButton with a4j:support

[Wolfgang]

Hi,

I combined a h:commandButton with a a4j:support component:
<h:commandButton id="submit"
                    value="Submit"
                    styleClass="submit_button"
                    actionListener="#{homePage.processSubmit}">
       <a4j:support event="oncomplete"
                    actionListener="#{homePage.processServices}"
                    reRender="tree, inputRegion, serviceError"/>
</h:commandButton>

Everything works fine besides that the method homePage.processServices 
won't be called
Does anyone know why?

Cheers