Htmlunit access to a frame inside a frameset which is inside a frameset

I need to access to a form element which is in the frame "menu"

<html>
<head>
<script>.........
</script>
<title>The Main page</title>
</head>
<frameset onload="init();" rows="70,*" frameborder="0" border="false" framespacing="0">
    <frameset cols="32000,0,0" frameborder="0" border="true" framespacing="0">
            <frame scrolling="no" marginheight="0" marginwidth="0" target="logo" src="about:blank" name="logo"></frame>
            <frame scrolling="no" noresize="" marginheight="0" marginwidth="0" target="temp" src="about:blank" name="temp"></frame><frame scrolling="no" noresize="" marginheight="0" marginwidth="0" target="system" src="about:blank" name="system"></frame>
    </frameset>
    <frameset cols="165,*" frameborder="0" border="false" framespacing="0">
        <frame scrolling="no" noresize="" marginheight="0" marginwidth="3" target="menu" src="about:blank" name="menu"> </frame>
        <frame scrolling="auto" noresize="" marginheight="0" marginwidth="3" target="work" src="about:blank" name="work"></frame>
    </frameset>
</frameset>
</html>

I tried this:

menuPage = (HtmlPage)page.getFrameByName("menu").getEnclosedPage();

But what I get is

<?xml version="1.0" encoding="ISO-8859-1"?>
<html>
  <head/>
  <body/>
</html>

I tried different other odd thing but never succeed to get the content of the frame..... If somebody have already done this I will be happy to get some clues..

Solution

Ok, I found it eventually. The javascript was loading. But besides and most important I was not accessing correctly the frame content. So By looking deeply in the dom with firstchild and sibbling I arrived to see what I was looking for. So the first code working is the following and need some tweaks:

HtmlElement frameset1 = page.getBody();
node = frameset1.getFirstChild().getNextSibling();
HtmlFrame fr1 = (HtmlFrame) node.getFirstChild();
FrameWindow fw1 = (FrameWindow) fr1.getEnclosedWindow();
HtmlPage p1 = (HtmlPage) fw1.getEnclosedPage();

Thanks for your time