Unable to add users into sharepoint if i am Using emails as account name in Active Directory

I am using moss 2007 version 12.0.0.6421. and Active directory version 6.0.. . my AD domain is siamint so if i add a user as vikas. it gets added in AD with logon name as vikas@siamint.com now if i add a user sahil@yahoo.com into ad. it gets added as sahil@yahoo.com@siamint. now when i try to add user from peoples开发者_开发技巧 and groups,site settings in a sharepoint site; i gets user siamint\sahil in people picker. rather it should be siamint\sahil@yahoo.com. it means the name is truncated from @. Is this a sharepoint error or what. Ultimately i think it means we cannot add users with @ in their usernames.

When you add a user to Active-Directory you give a "user session Name" (1) which is composed with the domain name (2) to give an attribute which is the real login name stored in an attribute called "userPrincipalName".

So "jpb@dom.fr" in the preceding picture IS NOT a mail adress but the UPN (userPrincipalName) of your user in Active-Directory.

Since Windows 2000 UPN is supposed to replace the old login string (3)

Edited

Sorry, it's in french, but as you can see '@' is allowed in the logon part of the UPN. Look in Microsoft documentation (Active directory naming) for more information.