i have test this:
create a new virtual folder or real folder
name it as you will by sample: test
put into advanced diff tpl
<html>
<head>
<frameset cols=200,*>
<frame name=progress src="/~sym-sidemenu.html" scrolling=auto marginwidth=0>
<frame src="/~sym-main" scrolling=auto>
</frameset>
</head>
<body>
</body>
</html>create a virtual folder into home directory and rename it ~sym-main
right clic to the folder and hide it
put into advanced diff tpl
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0
Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html>
<head>
<meta http-equiv="content-type" content="text/html; charset=UTF-8" />
<style type="text/css">
%style%
</style>
<title>HFS %folder%</title>
<link rel="shortcut icon" href="favicon.ico" />
</head>
<body>
%login-link%
%loggedin%
%upload-link%
<div id=folderlabel>folder</div>
<div id=folder>%folder%</div>
<div id=body>
%folder-comment%
%up%
%files%
</div>
<div id=footer>
<a href="http://www.rejetto.com/hfs/">HttpFileServer %version%</a>
<br />Servertime: %timestamp%
<br />Uptime: %uptime%
<br />Build-time: %build-time%
</div>
</body>
</html>
see your web page and select the directory TEST
html code as bug with frames
back button must desactivate frames created to work correctly
with javascript it is more easy to do what you want