I have successfully joined a samba 3.0.1rc server with security=ads to a W2k
AD-Server.
Connecting to a share works fine.
Our testuser has in AD a differnt username than on Unix (NIS)
Therefore we use a username map.
this is the log when connecting to the share
 NativeOS=[Windows 2000 2195] NativeLanMan=[Windows 2000 5.0]
[2003/10/30 08:34:38, 3] libsmb/ntlmssp.c:ntlmssp_server_auth(286)
 Got user=[maurerh] domain=[DLR] workstation=[ADRMPC042] len1=24 len2=24

When I try to connect to the computer
with the MS Snap-In "Admin-Computer" (Computer verwalten in german)
access is denied and samba logs the following:

NativeOS=[Windows 2000 2195] NativeLanMan=[Windows 2000 5.0]
[2003/10/29 16:34:42, 3] smbd/sesssetup.c:reply_spnego_negotiate(385)
 Got OID 1 2 840 48018 1 2 2
[2003/10/29 16:34:42, 3] smbd/sesssetup.c:reply_spnego_negotiate(385)
 Got OID 1 2 840 113554 1 2 2
[2003/10/29 16:34:42, 3] smbd/sesssetup.c:reply_spnego_negotiate(385)
 Got OID 1 3 6 1 4 1 311 2 2 10
[2003/10/29 16:34:42, 3] smbd/sesssetup.c:reply_spnego_negotiate(388)
 Got secblob of size 1270
[2003/10/29 16:34:42, 3] smbd/sesssetup.c:reply_spnego_kerberos(178)
 Ticket name is [maurerh@INTRA.DLR.DE]
[2003/10/29 16:34:42, 1] smbd/sesssetup.c:reply_spnego_kerberos(218)
 Username maurerh is invalid on this system
[2003/10/29 16:34:42, 3] smbd/error.c:error_packet(94)


If I create the local user maurerh on the linux machine
it works and i can connect. 

[root@rmcs01 pam.d]# more /etc/samba/smbusers
# Unix_name = SMB_name1 SMB_name2 ...
root = administrator admin
nobody = guest pcguest smbguest
maurer = maurerh

[root@rmcs01 /root]# testparm | grep map

        username map = /etc/samba/smbusers
        map archive = No