samba - Sep 2008 - Using local Windows and AD accounts with SAMBA

Question about shares and ADS vs. local Windows accounts. I have a NAS
(linux/samba based) set in ADS mode. If I'm logged into the domain with
user1/pass1, I can access shares. If I log into the Windows machine locally with
the same credentials, I can't access the shares. I have another older NAS
(linux based) where I can, so I'm thinking it must be some setting in the
samba.conf file, or else something has been changed in SAMBA's AD
implementation.

e.g./clarification
A share that is accessible to "user1" when he logs in to the domain is
not accessible to "user1" when he logs into the same computer locally
(using the same username and password).

Is there any way to change this?

Thanks for any help.