Thanks a lot for your time. I resolved that issue myself.
It seems the problem was that I was trying to do the SVreg process directly on pial surface, without hemisphere labeling. Performing hemisphere labeling step before registration resolved the issue.
Now I have the labeled surface with the 95 ROIs color coded. However, I’m not sure how to visualize any sulcal markings (the atlas description has 26 sulci). My primary motive here was to obtain automatic marking of those 26 sulci on the surface.