Freeradius + AD authentication passing Domain+User

[Alejandro Cabrera Obed]

Dear, we have a Freeradius 2.2.5 server in order to authenticate WiFi users
from cell phones and notebooks.

In the case of cell phones, the users type the corresponding usernames and
passwords and after that Freeradius passes it to the AD and everything
works OK.

In the case of the notebooks, the Windows users are logged into our DC
domain, then they type the username or username at domain or domain\username
with the corresponding passwords but in theses cases they can't
authenticate against the AD (there is a reject message in the Freradius
log). In case they are not logged into the domain, and they are local users
in the notebooks, if they type just their usernames (without domain) they
authenticate OK.

So how can I authenticate Windows users against the AD when they are logged
into the domain??? Do I have to define a special directive in a config file
from freeradius, winbind or samba?

Thanks in advance, regards!!!

Alejandro