DC join options?

[Aaron E.]

I'm looking to specify hostname and ip of the seoncdary DC when joining 
the domain as a secondary DC.. I've tried --hostname and --hostip but 
these fail as invalid options.. I've been looking through some scripts 
and haven't found the options for samba-tool domain join yet.. Can one 
of you guys point me to the proper place or help out with the options?

Thanks
Aaron