Crown Moulding

[Stinkerbell]

My room has vaulted ceilings but I want to use crown moulding.  My dh says it won't work because the walls where the ceiling vaults wont have a flush surface.  I was thinking maybe using a flat moulding on the wall and the ceiling, then using a 1/4 round or something in the center of those 2 to make them look like one.......  anyone have any better suggestions for me??