splitting a commit that adds new files

I usually start splitting a commit with "reset @^" then "add -p" back.
The problem is "reset @^" does not keep track of new files added in
HEAD, so I often end up forgetting to add new files back (with "add
-p"). I'm thinking of making "reset" to do "add -N" automatically for
me so I won't miss changes in "add -p". But maybe people already know
how to deal with this case without adding more code?
-- 
Duy