Well I tried but failed. I prototyped a few approaches but none of them are without big visual artifacts.

Physx assets are always are tricky to deal with in this game due to FXS's certain design choices on the engine. The only way to implement phyx on a cosmetic piece is to make it an "attachment" instead of "torso","legs", etc. The problem is the said piece can only be strictly attached to a single bone and only moves with that bone. This is not an issue with a cape(attached to the shoulder of a character) or a tie (attached below the neck) since that's how they work. However for boobs, you want them to interact with several bones in order to feel real (ribcage and spine as well as shoulders), which I havn't figured out a way to do so.

There are still ideas I haven't tried but they all look a huge violation of the KISS principle. Maybe one day I'll try that out, or some other modders can figure out a more elegant solution. Who knows.

if possible... please make only costume... I mean only the Torso,Legs,Arms and Hair that will compatible with Xcom Soldiers... I just love the bodies of your vocaloids.. :)