Do you know how to use the Cloth Room? If not, check out some of the dresses at PoserFashion.net. They come with detailed, step-by-step instructions. Dynamic clothing is completely different from conforming clothes.

If you do know how to use the Cloth Room...make sure that Vicky's body is entirely inside the dress at the beginning of the simulation. Change her pose in the first frame so nothing is sticking out. If necessary, scale her or the dress. Set the scale and pose as you wish them at frame 30, and the dress should drape and stretch to fit correctly.

One odd thing about sdvl's clothing: it comes in parented to Vicky. Sometimes that causes problems. Try parenting it to universe instead, and allowing some drape frames.