I think the problem you are encountering here is the third point from markschums post. Hongyu's corset does not have the morphs you applied to V4, so it doesn't conform properly.
You could use the "Morphing Clothes" utility from Dimension3D here in the marketplace to transfer the missing V4 morphs to the clothing.

After you posed the figure make sure you apply the magnetize pose that came with V4 to the clothing to transfer the joint control morphs.