When eps or xps is applied to the exterior of a stick built home prior to siding it is my understanding that house wrap can be omited as long as the seams in the insul are taped. I am working on a home with a lot of dormers/additions so there is a ton of step flashing which will allow water to leak by if it gets behind the vinyl siding. How is this situation best handled?
Is the black tape good enough to rely on 100% for this situation? Should I simply overlap the step flashing by an inch or so and stick it to the foam.
 Ideally the roofer/framer could have bent the flashing into the foam and adhered it there but that did not happen as I am sure it would have taken a lot of time.

Counterflash like on a masonary chimney. Bend an L and stick one leg into the foam and the other leg covering the top of the step flashing. You could even use matching coil stock to your final clad color to cover the shine of the step flashing. Bend a drip leg on the bottom edge of the portion covering the step flashing.