All CAS items share the same UV space. Each has its
designated area.
To avoid overlapping, make sure to place UV islands not only in their designated areas but also in the vacant space.
1). Select the body, switch to Edit mode ( TAB ), disable Limit selection to visible;
2). Select everything covered by the garment, press Delete and choose Faces. If the garment has skirt-like bottom, make sure to leave at least one row of faces. Otherwise these deleted areas will be visible during walking;
3). Enable Sync, select everything with A;
4). Click on Browse and choose any texture;
5). Shift-select the garment, select everything, choose THE SAME texture, check View - Draw other objects.
6). G to move, S to scale, R to rotate. Following the first two with X/Y will constraint transformation to horizontal/vertical axis. Following any with a number will move/rotate the selection by that number of pixels/degrees. By default UV space is square ( 1:1 ), but TS4 textures are not ( 2:1 ). UV islands that were generated in the square space will become stretched vertically when rectangular textures are applied. To bring them back to their original size, select everything in UV Editor, press S Y 0.5
Place the garment's UV islands in the right spot. Make sure to scale them uniformly unless some need extra definition ( buttons, zipper, other small details ) or are hidden ( geometry created to cover holes, back side of clothing, etc ).