Walls between split level roofs, and an extended gable

[NathanielK]

I cant find anything on what must be a strange wall between roofs. This first problem has to do with vaulted ceilings...

 

Here i have two rooms that share open space, but each on different floor heights (same floor in plan). They both have similar roof planes, but the higher room has roof raised about 2' higher than the other. This creates a space between the roof planes:

There is no wall in the rooms underneath this split roof, except the beams that will traverse from a central tower (at the ridge) downward to the outer wall baseline. I imagine the resulting "attic" wall must be built on a thick beam, but it will be framed, for support and strength, so it will be an actual wall (with either stucco or siding). I can draw this up on paper but i dont know what i need to do to assemble this (im using CA11).

 

Additionally, i need to build a dormer-type gable connected from the lower roof (using a vaulted ceiling, remember) outward to a projecting foyer for the front door. Every time i try to insert a gabled roof, the roof extends inside the vaulted ceiling. And i cant insert a dormer because it must extend past the main roof plane out to the front gable.

 

If anyone can help with one or both of these problems, i would greatly appreciate it. Even a link to an article or solution would be helpful.