Hi blender stack exchange, I've encountered this problem at work, where I try to make the pattern a metallic color, that should reflect the light on it, but instead it just lighten up the texture color. I've worked a little with the speccular mapping of the model, because I found some tutorials on youtube about it, but it seems like it isnt the way to solve this problem.
The best way to test metallic or mirror reflections is to have something to reflect. Perhaps the material IS reflecting correctly.
Use an HDRI environment or other method to create a known environment with light sources, colors, etc. Then you can better judge if the material is behaving correctly to metallic shaders.