External source for username en password

When i login using the joomla default mod_login.

It uses our authentication plug to check username and password this works fine.
But when i use the CB login module it doesn't .

Is that correct or do need to make authentication plugin for CB ?
Is ther some dev doc for that ?

Oke after disable the System - CB Core Redirect plugin,
THe login uses my auth plugin .

Now i need to find a way to submit my userinfo to CB.

Shouldn't need to disable CB Core Redirect if your form sends a POST to CBs login. You'll probably have an easier time reviewing the source of the CB 2.0 login module though as the CB 1.x module is more difficult to read.