Sure thing, mate 
Its actually really simple.
As I said, I rendered it in different passes. This gives me a very controllable image to work with in PS.
First I did the normal diffuse pass. Just the basic render with the texture.
Then I chose a specular shader and rendered it and exported it to PS.
I did this three times, using different shaders. The bright highlight is the work of the plastic toy shader.
In PS, I set all the specular layers to screen, and lowered the opacity.
I used a similar technique to the one Scott Spencer showed, some weeks ago I think it was.
Iām not sure if this helped, but at least I tried 
Henning