How to change current user

Hi guys:

I need to know (if there is way), how to change the current user. I mean, you log into mws with user A (and password) and into my portlet make the necessary modifications to become user B, without entering credentials.

best regards.

Please see this post: http://tech.forums.softwareag.com/viewtopic.php?t=23823

Regards,
–mark