Samba NT Domain Authentication Question

[Glass, Scott]

Greetings folks,
  I've got a strange request. We're using the Remedy Action Request System
here at Dow Jones and are trying very hard to come up with a method of
authenticating our users to our companies NT domain.  The one major gotcha
is Remedy is on UNIX and (of course) it's a Windows domain.
  Okay, so I've been using Samba for several years and I feel that it's my
golden ticket to accomplishing this task.  All I need to do is grab Samba's
authentication engine and "marry it" with the Remedy AREA server that
provides external authentication for the ARS.  

So my question is, what Samba source file(s) contain the authentication
engine that Samba uses to authenticate against a NT domain controller? 

Any help would be greatly appreciated.

Thanks,
  Scott Glass