[Centos] Centos4 RC1 problem adding machine in samba

I'm trying to install a samba PDC with Centos4 RC1, when I try to insert a 
machine name like:

>> adduser machine-name$

I had this response: invalid user name 'machine-name$' all string ended by $ 
do the same result.
In centos 4 beta2 I haven't any problem, run ok.

I have tryid too:

>> adduser machine-name$ --foce-badname

but says: invalid option --

Please, somebody have a solution? thanks!!

Jordi Arquimbau