one of the more simple ways is to apply a shader with the same colour to both surface. you cant just copy one surface to the other as this is a texture is on a single texture map so both colours are already on the texture map.
Another option is to make a copy of the texture and take it in to photo editing program and change the colour of the textures until they are both the same colour (make sure to save under a different name) and than you can apply this texture to the cloak. this would be for personal use only though as you would not be able to distribute it
Here is an example of just shaders applied to the cloak I just used some of the shader supplied with the supersuit