the accordion example in showcase with the page:-
accordionPanel.xhtml
uses
{code}
      <h:selectManyCheckbox id="list" layout="pageDirection" selectedClass="selectedCheckBox" >
                                <f:selectItems value="#{accordionPanelBean.toDoList}"
                                                    var="listItem"
                                                    itemValue="#{listItem.value}"
                                                    itemLabel="#{listItem.key}"/>
                            <f:ajax execute="@this" render="@all"/>
                        </h:selectManyCheckbox>
{code}
In order to modify this to ace:checkboxButtons or ace:buttonGroup, the layout attribute would be useful (rather than having to nest the component within another c:forEach tag). Currently, these components only are rended in a horizontal manner (no vertical ability to list the checkbox or radios)