divide/panel non rectilinear surface

Every time I divide the surface, it reverts back the the origin form in which I created my surface (rectangle before trim). I tried paneling via lunchbox and it still reverts back to the origin form. It may be that I need a new way to actually generate the form but I'm not sure how to go about doing that. Seems like there would be a simple solution, I'm just not sure of it.

Thanks for any help.