stacked wiindows with prism

Hi,
I'm trying to figure out how to create a window arrangement like this using actipro dock/prism:

-----------------------
A | |
------------ C |
B | |
-----------------------

Ideally, I'd like to have the ability to dock A & B as toolbarwindows (separately or as a set, I don't care).
Would I need a split container to do this?

How should I setup the prism regions? From Prism's perspective, I think I only need one region here, and let actipro handle shuffling windows within that region?

(It would be very helpful if you could produce examples showing how all the actipro dock features working with prism)

thanks!