add child domain to mantisbt

[giancarlo]

Hi everyone,
i'm new user about mantisBT. i installed mantisbt in my domain and,by this forum,i configured mantis properly and all working fine(authentication and mailing).
but now i've a problem:my company wants to connect to mantis also a child domain(authentication and mailing).
i've try to add a ldap authentication,but no lucky.
i search a post in this forum about the child domain,but i didn't find a solution.
can anyone help me?