import mesh with animation from blender, bone constraints arent working

hey, im working on a project on blender, and i want to import my meshes on unity. I have 2 different meshes with 2 different armatures (the main body and a dress ), i have copied rotation/location (via bones constraint) so the dress moves around by copying the location and the rotation of the main body's armature. When i tried to import these meshes on unity (fbx files), in the RIG tab , i chose HUMANOID and the configuration was OK without any warnings, but the dress didn't follow the animation flow of the main body. Also, i've tried the GENERIC RIG, where everything worked fine, but when i tried to rotate the offset so to change the actual location of my mesh, the dress didnt follow the animation flow again. As i got, there's probably a problem with the bone constraints, because the dress armature did not follow the character armature correctly. Is there anything i can do for that?