You can also look at the Developing a DCE device page in the wiki, as well as the Developers guide.
Essentially, DCE devices of this nature are interfaces, they translate DCE messages to the native messages for a given bus, and vice versa. We have device data so you can keep track of things like addresses of devices on a bus, and assign them to the dummy light bulbs etc, and the interface device will receive the commands for those children, and can grab the associated device data, and do the right thing.
There are plenty of examples of interfaces in our source code tree, under src/, CM11A, and ZWave are two such devices interfacing with said busses.
And, if you can get on IRC, we can help navigate you through the code and get you to where you can write a DCE device to control this bus.