Centos 6.7 and Winbind with active directory

[System_Admin]

Hi all,
I am trying to authenticate windows users to Centos 6.7 box. Users from active directory can logon to the Centos box, however "sudo -s" command is not permitted due to the incorrect username displayed at the linux prompt. "Who" command lists the windows username correctly, but somehow the command prompt displays the names as [guest@linuxbox~]# instead of [windows-username@linuxbox~]#. Because, it assumes the name as guest the "sudo -s" command presents challenge for guest user instead of the windows user. Widows group is correctly added to the /etc/sudoers file.

Thank you in advance for your input.

Cheers.