I don't know if this is something that has changed in Blender but when I go to assign the "Paint" image for painting on in edit mode to pants/shirt it comes back with "missing data" in the Texture Paint tool panel with an "Add a paint slot below." Adding a paint slot creates a separate image in the image editor, so we're left with separate images rather then a combined image for the paint layer. Obviously these can be combined in Photoshop but I'm wondering if there is something I'm doing wrong, if it's a change that has a workaround, or if it's a bug.