We are somewhat unhappy with the monolitic design of IMHO. Every new features needed lots of work and plugins support is just unusable for ISP usage.
There were too much hardcoded things and IMHO is not really expandable, every modification could produce some unwanted side effect, so it not really usable in an ISP or B2B enviroment.
The "multi-modules" model, like Pike or Caudium (or Roxen) modules was rejected by the IMHO developers because of historical reasons... That resulted in a product in which it is hard to add new features, or to correct bugs.

Before Camas was born, the project was handled by Cable & Wireless France for its own customers. Some of their modification have been merged into the current IMHO code.
Suddenly Roxen 2 came out. Being (largely) incompatible with Roxen 1.3, and the fact that the maintenance of Roxen 1.3 has stopped, quickly made the situation clear. There were two solution: either move to Roxen 2.x or to use Caudium.
CAMAS is Caudium's port of Cable & Wireless France IMHO modules and thusis an independent product from IMHO.

The IMHO documentation is almost a nightmare. There is barely any developer's docummentation, the RXML tags have lots of of undocumented options (that you can find in our current documentation named "To be documented").
Adding new features needs a high level understanding how is handled internal data in IMHO. By creating provider modules with easy API, people can create their own options or new features without understanding totaly how data is managed in CAMAS... For example, the camas auth module is a very good example.
We will trying with the help of Caudium autodocs system to document most (and we hope all) internal, tags, entities, etc... that Camas use to help either core developer and user interface designers.

Well... It is designed to run on Caudium and Caudium is also designed to run Camas too. Camas may run with Roxen 2.x, but it needs modifications or modifications of Roxen's core to be handled.
Anyway, we are open and if some skilled Roxen developper wants to make a port of CAMAS for Roxen 2.x, he will be welcomed to be a new member of the CAMAS developpers team.