Word Press Otrs

[ebonheart]

I have a wordpress support site which is connected to an AD in my company.
I use otrs for the ticket system in my wordpress site.
The users log in in my support site, with their AD username and password.
The problem is that when i redirect them to otrs for the ticketing system, they have to log in again.
i tried ?Action=Login&User=<user>&Password=<pass> but it doesnt run.
My question is the problem is Auth ? and if yes what should i change in the Auth code in my config file ?