samba - Dec 2006 - : Samba environment variable for Windows(%USERNAME%)?

Hi,

I am running Samba 3.0.23D on AIX server with LDAP backend.   For security 
reasons,  I want to ensure users are logged onto their Windows 
workstations with the same userid they are connecting 
to the Samba share.    I know via Samba environment variables that I can 
capture the effective share userid(Samba env var %u) but I am looking for 
a way either via Samba environment variables or other mechanism to tell 
Samba to capture the Windows client username(%USERNAME%) so that I can 
reject access to Samba share if they don't match.

Thanks in advance,
Maurice Forte
Email: mforte@us.ibm.com