To answer your 2nd question; yes, you can and *must*  save the model as a new  .obj file! You import your .obj model file in UV Mapper> make your UV map> save your UV mapped model out of UV Mapper under a new name in a different folder(for safekeeping, and to avoid confusion) and then save your UV map to the same folder. You will not have to name it because if you name your UV mapped model before you save it to the new folder, the map will already have the correct name, only it will be "something.bmp" instead of "something.obj". Then you import the new UV model into Bryce, or other app. Then you import the UVmap bitmap and apply it. Look at the screen cap to see where the model save option is on the menu. HTH