You  need to do your user mapping through the /etc/usermap.cfg file on the filer.
 
http://now.netapp.com/NOW/knowledge/docs/olio/guides/ontap_troubleshooting/usermap.shtml

From: owner-toasters@mathworks.com [mailto:owner-toasters@mathworks.com] On Behalf Of Langborg Tom
Sent: Wednesday, February 28, 2007 10:07 AM
To: toasters@mathworks.com
Subject: usermap problem

Watch out.

I got usermap problem after uppgrade to 7.2.1.1.

I use ldap.usermap for usermapping.

The unix name are not the same as windows name.

With unix name same as windows name it still works.

If there are someone who now any fix for this problem,

Please send me a letter.


Regards

tom