I have created a new face via Facegen customizer and got this new face as InternalMeanFace in Facegen modeller. PFA new face (csamface) and generate new faces (.fg file). I am now using FaceGen2Rex to use this new face with .tri and its .mesh file to get a new mesh with the face applied and get a new mesh and its new .jpg. Earlier for jack realxtend avatar we had a .cfg which contained Ogre fitting parameters for face to fit on the Jack.mesh. If we don't supply this .cfg value for the newface.tri what we get is a distorted .mesh file as output.
Let me know how we can add images to showcase the problem or any email ID where I can post the complete steps I am following.