passing parameter to workplace

Good morning,
we have this type of situation:
we use workplace as master menu of all our application, and the workplace itself is inside a frame being part of a web portal.
While user are already logged in in web portal, we would like to pass to workplace (and consequently to all application launched from it) the user account of the web portal.
How can we manage to pass this information to workplace?
thanks and best regards
Diego Gazzo