According to the description on the Microsoft website, about nfsadmin syntax: casesensitivelookups={yes | no}:
This section applies only to Windows Server 2008 R2, Windows Server 2008, and Windows Server 2003. This section does not apply to Windows Server 2012 R2 or Windows Server 2012.
we still can use nfsadmin to configure case sensitivity for Server for NFS.
Nfsadmin
http://technet.microsoft.com/en-us/library/cc771599.aspx
Note:We need to disable Windows kernel case-insensitivity in order for Server for NFS to support case-sensitive file names. We can disable Windows kernel case-insensitivity by clearing the following registry key to 0:
HKLM\SYSTEM\CurrentControlSet\Control\Session Manager\kernel
DWORD “obcaseinsensitive”