[Samba] mapping home directories using samba/ADS when users accts don't match

[Lisa Smith]

Am currently migrating from a samba/nis authentication scheme to 
authentication thru Active Directory.  I currently have everything set 
up and "ready to go" with one minor caveat.

new users are set up correctly, with authentication through AD and have 
a unix drive mapped to their W2k work stations.

however, pre-existing student accounts are not synchronized.  There is 
no way to tell at this point whether jsmith1 on the samba box matches 
jsmith on the AD. 

Shortly, I will have the data I need from the registrar to match our 
user list against theirs, but I'm not sure how to get samba to "read" 
this information.  Where can I go about in (samba?) setting up a 
configuration that will read a mapping of samba/unix uid to the windows 
AD/uid.    

Does this make *any* sense?  

All I want at this point is to RTFM, so if someone can point me to a FAQ 
about incorporating prior users into a new AD/Samba authentication/drive 
mapping scheme, that would be great.

thank you,
Lisa