Thanks Josh !
So, to summarize:
1. AD Config as per section 8.4 Admin guide
2. SAP Authentication in CMC
3. STS / Server side SNC (I already have the SU01 SNC in BW (i..e GUI users can login to BW without a password))
4. Map AD users to SAP users:
http://wiki.sdn.sap.com/wiki/display/BOBJ/How+to+map+SAP+users+and+AD+users+in+XI3.1+CMC .+ Note 1343537
In step 3, which one is preferable......STS or SNC...please suggest.....
Thank you
-S.