PA Web Server and integrated WIndows security

Hello,

What exactly has to be done to enable direct logging of user to PA WEB server, from Windows domain account?
To log on to PA client it works with domain user credentials, but when try to open Report Menu, it brings me to login page of Web Server.
Same user is correctly defined in Web Server User Tree, with "NT Domain\UserId" filled in, but simply doesn't work. It accepts only local PA username and password. Windows authentication is enabled on IIS, and there is no problem.

Thanks