Accessing Portlet Session parameters in Freemarker

Hi,
Iam developing a Spring Portlet application with Freemarker as the view.

As part of my application I have to add some attributes in Portlet Session and 
access those in the Freemarker template files.

currently when I try to access the values in the values in the template files 
Iam getting the InvalidReference Exception.

I tried accessing the Session parameter values like below.

${Session.productType}

and I got the below exception.

***********************
Expression Session.productType is undefined on line 9, column 3 in login.ftl.
The problematic instruction:
----------
==> ${Session.productType} [on line 9, column 1 in login.ftl]
----------

Java backtrace for programmers:
----------
freemarker.core.InvalidReferenceException: Expression Session.productType is 
undefined on line 9, column 3 in login.ftl.
***********************


can any one please let me know how to access Portlet Session parameters in 
Freemaker template files.


Thanks,
Sunil.



-------------------------------------------------------------------------
This SF.net email is sponsored by the 2008 JavaOne(SM) Conference 
Register now and save $200. Hurry, offer ends at 11:59 p.m., 
Monday, April 7! Use priority code J8TLD2. 
http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone