Hey Rob, my initial thought of using transparency was actually wrong. I was visualizing, but couldn't remember exactly what I had done recently while playing with some textures. What I was thinking was you'd have your regular texture map for the whole outfit, and a separate texture map with just the emblem you want to put on the back. That's accomplished with placing the transparent color, in my case white, over everything else, but the part I wanted to show.
What I did come up with for you, and again, this depends on whether you're actually using the UV map. From what I see in your screenshot above, it appears you're only assigning the red color to the diffuse. What I'm thinking you need to do is texture the UV map like the following. I only bothered with the jacket so you can see the placement of the emblem on the UV map below the red color. Needless to say you would have to texture the whole map for the rest of the items in the outfit.
View attachment 9492
That said, I thought you should know this particular image has been used, or a very similar one has been used, on one of the textures in the World Jacket texture set for Dusk's Bomber Jacket here in the store.