I think you can't make the texture shiny unless you use a shader for this.
As I have no real experience with this I won't be a real help but have a look
at TestNormalMap (I think that is in jmetest.model.loader or something like this).
There you attach a shader with texture(diffuse), normals-texture and speculartexture <--shinny
But I don't know if that takes lights in account! For that search for per-pixellightnings.
I think in the wiki there is a link....
Sry, that I can't really help but maybe I pointed more or less in the right direction. Good luck
EDIT:
http://www.jmonkeyengine.com/forum/index.php?topic=8978.msg69603#msg69603edit2: hmm, afaik you have something like shadersupport in sceneworker...