[Samba] PAM session trouble

[David Wright]

I am using PAM and pam_smbpass.so with Samba 2.999 (Debian sid package).

If, in /etc/pam.d/samba, I set
   session  required  pam_smbpass.so
then login fails, and the log says:
   [2002/08/04 15:43:26, 0] auth/pampass.c:smb_pam_error_handler(73)
     smb_pam_error_handler: PAM: session setup failed : Module is unknown
   [2002/08/04 15:43:26, 1] smbd/session.c:session_claim(103)
     pam_session rejected the session for ichbin [smb/1]
   [2002/08/04 15:43:26, 1] smbd/password.c:register_vuid(285)
     Failed to claim session for vuid=101

If I set
   session  required  pam_permit.so
then there is no problem, although auth, account, and password are still 
set to use pam_smbpass.so.

Does this mean pam_smbpass doesn't implement session? If so, what should 
I use instead? If not, what is going on here?