Planting native flowers couldn't hurt, but as with their Annona relatives, a decent yield of pawpaws will most likely require hand-pollination. People do it, and it works. The flowers are protogynous (effectively female first, then male), so you'll need to collect pollen from the flowers that are in the male stage and use it to fertilise the flowers still in the female stage, then repeat each day until all flowers have been pollinated. Your devotion shall be rewarded.
EDIT: Thank you for the informative post. Anyone in pawpaw territory would do well to research the plants that you linked.