QMail and Win NT user auth

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Hello to everyone,   My company has the mail server running on Exchange 5.0 (needles to say it works like hell) and I would like to move all the accounts on Linux QMail: PROBLEM: Is it possible to authentificate the QMail users against the an NT station?   -->(at this time when the user logs on to check his mail on Exchnage he uses the same user/pass that he uses to log on to the local domain) <-- I mean ... Is there any way that I can use the same NT Domain Logon based system (the file) to auth my further QMail users when checking  their mail.   If so PLEASE tell me how or give me some links...   Thank you Regards, Victor