Did you replace the wall with the fixtures, meaning did you replace the drywall or green board or durarock?
If you did, did you replace it with the same thickness of wall that was there originally?
If you did, then its the fittings of the new tub.
This does present quite a problem. You do have several options that I can think of: 1) install 1/4 inch drywall on that wall and build it up. 2) Install a quarter round piece of oak to make the transition. I do not like this too much because of the water that will normally be in that area.
Is the wall area going to be by chance ceramic tiled? If so, there is a special piece for that situation that will work.
If you are not planning on tiling, then we are back to square one.
Be patient and wait for others to log on to this problem and surely someone will give you some more advice. Wait until you do anything else.
You might come back on and answer some of my questions and see what we get.