authconfig --winbindjoin=... working

anybody been able to get authconfig --winbindjoin=... to work (on F7)?  
No matter what I try, all I get is python exception: 

Traceback (most recent call last):
  File "/usr/sbin/authconfig", line 780, in <module>
    module.run()
  File "/usr/sbin/authconfig", line 375, in run
    self.writeAuthInfo()
  File "/usr/sbin/authconfig", line 354, in writeAuthInfo
    self.joinDomain()
  File "/usr/sbin/authconfig", line 342, in joinDomain
    self.info.joinDomain()
TypeError: joinDomain() takes exactly 2 arguments (1 given)

I've tried 
--winbindjoin=<admin_user>
--winbindjoin=<admin_user>%<admin_password>

Any hints/ideas?  or is this a bug?

-- Rex