It could be that because we use open likewise which is free, this feature is not available. But enterprise grade package should be having the feature.
I find that configuring samba and kerberos is not that difficult as well. There are a lot of docs available and you need to just configure a couple of files and you are done. This method as well needs you to join a domain before you can authenticate and this might be the reason likewise behaves this way. As it also changes kerberos and samba files and uses these packages.
But I think this might not be entirely a Linux backdrop. Windows AD is developed completely keeping in mind windows clients.

Chaitanya..
Long Back I configured Fedora DS where Linux / Unix and HP Machine could easily authenticate.
Now The challenge is Making Fedora DS to join to ADS.
And also, two different concerns to check:
1. Say the ADS and Fedora DS are synchronized.Whenever I add any user in ADS should reflect in Fedora DS instantly.Is it possible?if yes, Can you send the link or docs?
2. I want only a few users in Fedora DS (we sysyadmins) restrictively to login to those certain Linux Hosts.
is it possible? If yes, can yu send me the docs?


I would be grateful if yu can clear these doubts.

I havent looked at fedora DS since long so I can not help you much on that. But that should not be impossible.