Have CB Subs 1.2.2, CommunityB 1.7.1, Joom 1.7.2, running MySQL 5.1 and PHP 5.3.6.
Setup User Groups for access areas on the site under the Registered group so it looks like this:
Registered
--Members 1
---Members 2
----Members 3
There are 3 plans and they are assigned to 1, 2 and 3 respectively in the User Groups. When someone pays on CBSubs the payment is processed but the user account is blocked and the user is automatically placed in the Members 1 area.
Email activation is turned off in CB and User Registration has been turned off in the Joomla User Groups area.