How to build a self contained composting toilet like the commercial models for my tour bus?

I want to build a composting toilet with a finishing tray like the commercial units that I would only have to dump once a year. I need to know how the internal workings function. i will have solar heat piped into it to keep it hot.

People like Sunmar have some schematics of the operations of their units. Why not just fit one of them ? Compared to the risk of getting it wrong, an off the shelf unit, solar heated by your ingenuity seems like a darned good hybrid solution. Steve
I've used a composting toilet before and they are hard enough to keep working right when engineered to work right. This is not an area for self-experimentation. Especially in a moving enclosed vehicle. Look into one of the production units, or just plan on making a stop at every McD's.