CJAX and CI - responses vs controllers - accessing CI goodness

[eluser]LordMatt[/eluser]
Please forgive me if I sound cross it is because I am feeling cross. I've spent a week trying to make CJAX work and it is a slow and painful process that seems to involve a lot of me yelling at the screen "what the hell is that even for?"

Am I labouring under the misunderstanding that CJAX is an AJAX framework for CI? So far all examples would work better and faster WITHOUT Codeigniter which mostly seems to exist as a massive amount of cruft. The lack of decent documentation is hurting my head so badly...

My understanding is as follows.

When I want CJAX to respond to requests and stuff I put classes in the responses folder. This seems to work for the does-not-in-any-way-appear-to-use-CI examples.

So far so fine but what is the point of hanging all that goodness on the power of CI and then isolating me from it?

Why are responses being used separate from controllers? Actually don't even answer that question just tell me how to get access to the same power I would have in a controller (the CI framework) so I can use models and plugins and all that and actually access my business logic and data layers and do something worthwhile with the AJAX other than trying to pretend I have an AJAX UI and proper separation of logics.

As far as I can see Codeigniter does not exist during responses which seems more than just a little bit pointless.

Please, please, please help me get CJAX doing something even halfway useful.