Very few will read this question here, would be better to ask in the GateIn forum: tinyurl.com/2dr9m3w
Short answer though, GateIn supports JBoss Negociation tinyurl.com/262lhhb which does what you want
How can we implement desktop SSO? What I mean is if you have already authenticated via active directory to your desktop, and then I go into gatein portal, it will automatically log me into the portal. Can it use NTLM etc?