Joining AD domain

I’m attempting to join an AD domain as per the instructions here. The problem is, it doesn’t seem to actually work. Following the directions under section 8.3.2, or procedure 8.1, Joining Active Directory using User logon management, everything works according to the guide up until the last step where the window shows a blank entry for “workgroup.” I don’t think this should cause a problem, since there is no work group in this domain, but attempting to enroll fails with a message that the workgroup field is blank. There is no workgroup, and there is no way to edit that field, yet I cannot join the domain without it. I am able to join the domain on a CentOS box just fine. Any ideas? Thanks.