How do i attach a new mesh in edit mode on blender?

Hey, I've made these tie-up mesh tops and I can't seem to figure this out.
so I edited an ea mesh then created a sphere in the same layer in edit mode so it looks like this 



But when I load it up in sims, the tie up ball is floating around the room and not attached to the shirt, how would I go about attaching the sphere to the shirt so it doesn't move?
Heres the blend file  simfileshare.net/download/443423/

Thank you, SimmerKate