On normal stock h: components, ICEfaces 'decorates' forms in order to add stuff needed for form submission. This includes:

      <input name="ice.window" type="hidden" value="fbgs26iu6l" />
      <input name="ice.view" type="hidden" value="veamhp42" />
      <script id="hForm:hForm_captureSubmit" type="text/javascript">
      ice.captureSubmit('hForm',false);ice.captureEnterKey('hForm');</script>

This work is done in a class called FormSubmit and is implemented as SystemEventListener that listens for HtmlForm components that trigger PostAddToViewEvents:

public class FormSubmit implements SystemEventListener {

        <system-event-listener>
            <system-event-listener-class>org.icefaces.impl.event.FormSubmit</system-event-listener-class>
            <system-event-class>javax.faces.event.PostAddToViewEvent</system-event-class>
        </system-event-listener>

While this strategy appears to work fine in Mojarra, the form decorations are not being applied when running under MyFaces and the Ajax request is a postback.