I'm having some problems making plane mods, and wondering if anyone has the answer or has tried this ?

I have the 4*120 that was provided by one our our good friends here. I'm trying to modify it to include flaps but no matter what I try I cannot get the wing configuration to change. Initially I wanted to make the ailerons into flaperons, just as the 4* is designed, but cannot find a way to make this happen either.
However, I was able to change the engine and engine sound no problem.

Steps I followed were 1) make copy of plane from edit 2) Go to Main Wing pulldown in control surfaces section, shorten main wing length 3) click on has flaps and make dist to tip to be length from tip of aileron plus an inch. Do a save. G2 goes to reset the plane but it is exactly the same as before, no changes ! Anyone know what I'm missing or how to do this properly ?