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?