Use the main package shape as a mask for the squares. To make a mask press Command + 7 or go to Object Clipping Mask > Make.
Place the military pattern behind the highlights. Fill the reflections with a black to white gradient and select Screen in the Transparency Palette. This will make the reflections blend seamlessly with the color below it. Also, adjust the reflections' Opacity if need be.
We'll want the squares to have a slight distortion so they fit better when we place them over the packaging. To do this select them and go to Object > Envelope Distort > Make with Warp. Select Flag and enter a subtle variable to add some movement to the squares.