Simply put, in DS white on the trans map means the mesh is visible, black on the trans map means the mesh is invisible, and varying shades of gray give varying degrees of transparency.

If your transmap is the usual Poser kind, then it's just black and white with very little to no gray, which means that part of the mesh is visible while the rest of it is invisible, the classic example is the stocking, in Poser you get the whole thing, in DS we get the stocking top and the seam down the back of the leg and nothing else.

It means new transmaps with gray instead of black in the transparent areas, either that or learn how to use the Shader Mixer or the Layered Image Editor (LIE).