Microsoft made an improvement when it comes to Windows Server 2008 R2 to UNIX and MAC systems Integration.
How to Connect windows 2008 server R2 to UNIX and MAC systems ? Follow those links in order to setup Services for NFS, Subsystem for UNIX and connect UNIX servers to active directory

How to Install NFS on windows 2008 R2 server
How to Configure Active Directory for UNIX
How to Configure windows 2008R2 Server and clients for NFS
How to Create NFS Shared with windows 2008 R2 serve
How to Configure windows 2008 R2 Identity Management for UNIX