Here is the envelope file which I am actually working on.
I actually can’t understand why the front part of envelope (my own image) do exports to Bryce, since it had another texture before that from model used.
The orange color do not export and stay grey in Bryce. I understand what you say about the face must not be blue, but white. My menu differs from the 1 you shared above, though it looks somehow different?
Am I on the right track where it shows color: front - white /back - blue on image? And the styles menu you share above, is it same as attached image? I was looking all over interface, and got only this showing styles. Should I turn the back color to white on color wheel?
Excuse if I am not quite understanding. Firstly, I am not very good in English and secondly I am almost 64 years old with a brain not quite focusing!
Reverse faces turns back white as it was before adding color used.