Here's an example of using a mask to control what is metallic/mirror, and the inverse of that mask for diffuse value.

Firefly render:

Superfly render (using metallicity in the PhysicalSurface root); I think I have the roughness of the metallic/mirror areas too high:

You can render the PoserSurface root in Superfly, though I zeroed out the displacement since Superfly doesn't have micropoly displacement.

Poser 12, in feet.  

OSes:  Win7Prox64, Win7Ultx64

Silo Pro 2.5.6 64bit, Vue Infinite 2014.7, Genetica 4.0 Studio, UV Mapper Pro, UV Layout Pro, PhotoImpact X3, GIF Animator 5