Help: Assigning a "normal map" to a Material from a script doesn't work.

Hi there,

I have a script that takes a simple json and populate a material with texture maps. It's working perfectly for Diffuse, bump and Glossiness but doens't work on normal map.

The error I'm getting is  TypeError: Result of expression 'prop.setMap' [undefined] is not a function.

EDIT:::::  Nevermind I figured it out.  it seems like for Normal Map I need to use prop.setValue() instead of prop.setMap()..

Anyone knows why some properties requires setValue() instead of setMap() ?