How to set up SSO for OTRS?

Question

OTRS

Good afternoon everyone, please help me figure out how to set up SSO for OTRS.
It costs Ubuntu 13.04 to put the latest release of OTRS 3.3.5 on it, made authorization for domain users according to the instructions OTRS + win server 2008 LDAP how to overcome it? everything works great, but there was another question, people do not want to enter a password, they want to log in automatically, I read that you can set up pass-through authorization for OTRS. But I could not find the ideology of tuning anywhere.
Tell me how and what is needed for this?