Two roof pitches on same wall on 1 1/2 story house

[cstinem]

One more question on this, in the image I had attached previously, you can see where the 4/12 roof meets with the 12/12 roof line - how do I get the outside with the siding without having the siding on the inside wall? When I go in and change the inside wall to drywall then that changes the outside to drywall also. How do I get the wall on the inside to show only the drywall without affecting the outside wall?