So I've had this question in my own projects with Studio Neo, and I found a really ghetto way to get around it. There might be a built-in, much easier way to do it, but I never found it, so here goes:
Drop a duplicate of your character into your studio neo scene, have them take off all clothing/accessories EXCEPT the piece you want displayed, and then give that character invisible body. You now have a floating piece of clothing to do with as you will. Granted, this looks way more natural for shoes/boots/accessories, but with some clever maneuvering, you can get clothing to look like it's lying/resting on the ground/bed/etc.
As a side note, I went a step further when I wanted only one shoe to be present in a scene. I went into character creator, loaded up the character, and edited them so that they only had one leg. Repeat the above process, and now you have one floating (movable) shoe for your scene.
Additionally, if you wanted a piece of clothing to look 'empty', you can go into character creator and change the proportions of the specific body part to appear unnaturally flat, and then use the abovementioned invisible character trick in Studio Neo, and then you should have a flat-ish looking piece of clothing that you can move around.