Clarian provided some useful input...
Might be worth a look. I certainly haven't figured out face structure yet but I know the variables are there.
As an update, I just did scalar vectors as well. These are important because they control how light reacts with surfaces, especially hair:
As you can see, this makes a wealth of difference. In total the makeup, eyes, teeth, hair colour, brow colour and skin tone all changed. What this demonstrates is that it is entirely possible to bring in appearances from your ME2 save.
Original link: http://social.bioware.com/forum/1/topic/323/index/9661093/114#9780245