photoworks, reflective room & environment

Hello,

I am not sure to understand how PW works with environmant and
reflection and I've read many document found on the web.

If I set my room to reflective and put some light, I can see on my
part the pattern of the walls if the material is reflective.

If I set an image in the environment, I can see this image in my part
and set the amount of reflexion.

Are they working together?

The image in the environment has a reflexion setting, is it related to
material reflexion?

I am working with low indirect illumination for testing for now. I am
trying to render a simple white box made of shiny plastic and want to
see it white. For the moment it is always either grey or with a color
of the environment or tinted by the image of the environment (i used
the stock ones from SW).

Is the environment effective to do render or I should stick with a
scene with lights and indirect illuminations?

Thank.