Broswer is sending NULL Domain name

[sloke1 0]

We are trying to implement Windows integrated authentication using NTLM v2.0 for all HTTP traffic. Every thing is working fine when the system is logged in to the domain. But when the system is not logged into the domain, Firewall gives us a challenge window and asks for the username, password and domain name. When we enter the credentials, browser sends the right user name and password but does not send any domain name. It sends NULL as domain name. We have NTLM v2.0 enabled on the domain. Is there a way to make browser send the information to the firewall.

 

Thanks in advance.