[Samba] Question re: samba 4 feature set

[Coy Hile]

In what I've read so far about the proposed features for Samba 4, I see
mention of using a Samba 4 Domain Controller.  Is support either 
present or planned to integrate the SAMBA 4 DC as a second or third DC?
(That is to say, to join the Samba 4 DC as an additional DC for an 
existing 2003 or 2008 domain?)  All of the documentation that I have 
read so far addresses the situation where  the Samba DC is the first
DC in the domain.

thanks,

-Coy