Mesh disappears from behind in S4S

Hi.
1). The normals are just flipped. You must have noticed that in MD those patterns are grey, those are their inner side, you can flip them there by RMB-clicking on them and choosing Flip normals. In Blender select the garment, switch to Edit mode ( TAB ), select one face on each pattern at the back, Mesh - Normals - Flip normals. It's best to disable Backface culling ( displays geometry as double sided in Blender ) and switch Shading to Solid;
2). If you already transferred the weights, they did not transfer at all ( probably had a reference hidden or did not hold Shift). If you did not yet, you should never join the body before making the garment fully functional. Weights and uvs never transfer right for the body because fingers are too close to each other.
3). Clothing with loose sleeves should be made with arms down. Try transferring weights and checking how the garment animates in CAS, you'll see why;
4). The mesh is not vertex painted, it will not morph anywhere but breast;
5). The higher the density of your garment, the longer it will load, the worse it will morph and animate ( "cramped paper" way ). Ideally you would want to retopologize it ( MD 9 offers a tool for manual retopology, there's instant meshes addon for Blender), if not, at least switch to quads and raise Particle distance. Otherwise you are winning nothing with this, it does not even look smooth;

6). Did you remove doubles to reduce polycount? Should not do that to the body. I mean, you should, but only to remove the seam that goes right along uv islands borders, so with Merge distance set to 0,0001, nothing else, this messes up how it animates;
7). You garment goes below the level where most tops end. You should transfer a uv_1 map ( and weights) either from the top of the same length or longer or from a full body outfit. Otherwise it will not morph with the pelvis. Also use Nearest face interpolated instead of the default option

8). This has to be my punishment for something I've done in the past life. Every third if not second person who comes here seeking help with clothing related stuff has their uvs in that same goddamn bottom right corner. Why people who taught all of you to put them there never wondered why all of their cc's textures overlap with each other is beyond me. Please set this image as a background and cram those uvs anywhere in the space meant for tops other than that damn corner. Avoid it like a plague unless you're making a full-body outfit ( but even then you're not safe because people put accessory uvs there, GOD, full CAS of items with uvs in the same place).
Anyway, currently your uvs are in the space meant for shoes, bottoms and the neck. They are also stretched vertically. The uv space your garment's uvs were generated in is square ( 1:1 ), while TS4 textures are rectangular ( 2:1 ). When you set the rectangular texture as a background or import your blend file in s4s, the uvs adjust to the rectangular textures by stretching vertically. So before you decide where to place them in the uv_0 map, you need to shrink them in half ( select all, press S Y 0.5 ). This will bring them back to their right size.
It should look something like this

9). The more of the body covered by clothing you'll delete, the more space for the garment's uvs you'll have