I'm not sure I understand the problem Pete. Texture and shader not showing up where? In Silo or in Maya? Is it showing up partially correct somewhere?

Obj is a bit of a dinosaur of a format, only prolonged by being widespread and oh ZBrush picking it up haha.
Obj seems to save .mtl files which is basically just the diffuse, ambient, spec values. You'd typically have to load any textures separately regardless of application.

I've not had time to look into Silo 2's UV/material tools yet. So far only been using it as a modeling app, and the default shaders works great for that.