house wrap or foam baker board first.

we pulled off the siding for replacement (steel siding) and replaced our windows with new construction windows and flashed them like tyvec showed, My question....mabe too late, is we used house wrap over cedar siding that ties into the window flashing, but shouldnt steel siding have a backer board, behind it (Styrofoam) and is that O.K. to put OVER the guardian guard house wrap? Man if this is screwed up, Im in real trouble. Also I just read that a foil type wrap is good for steel due to heat and cold transference????