Changing Ofbiz's default menu html template

[Lei Wu]

Guys,
I was trying to create a new visual theme for my application based on
Ofbiz. As I was trying to customize the menu part, in CommonMenu.xml,
I saw the app menu is defined as :

    <menu name="CommonAppBarMenu" default-menu-item-name="main"
id="app-navigation" type="simple"
title="${applicationTitle}&amp;nbsp;"
        default-selected-style="selected"
menu-container-style="button-bar tab-bar"
selected-menuitem-context-field-name="headerItem">
        <menu-item name="main" title="${uiLabelMap.CommonMain}">
            <condition><not><if-empty field="userLogin"/></not></condition>
            <link target="main"/>
        </menu-item>
    </menu>

And in html, it looks like this:
<div class="button-bar tab-bar">
<h2>MsLi</h2>
<ul>
<li>
 <ul>
  <li class="active "><a href="/msli/control/main">Main Page</a></li>
  <li><a href="/msli/control/expensesInputs">Expenses Input</a></li>
  <li><a href="/msli/control/expensesList">Expenses List</a></li>
  <li><a href="/msli/control/expensesAnalysis">Expenses Analysis</a></li>
 </ul>
</li>
</ul>
 <br class="clear"/>
</div>

I'd like to change this html structure to something I want, but I
searched all the files and found no place where this html template is
defined. The definition in CommonMenu.xml only covers the css style
used in this html template. Could anyone who is familiar with this
menu template help me out here ? Thanks so much in advance !