The flowers are pollinated by carrion flies and beetles. The petals even resemble dead flesh a bit. Even with two plants flowering, I've read pollination can still be an issue. Those that grow them in containers swear by hand pollination which I might do to start. There was a tip posted somewhere saying to hang chicken skin among the branches... though that's just going to attract the neighborhood cats and other hoodlums to the yard.
Another thing worth noting is that wildlife love the fruit even more that you do and often big bites are taken out of them before they're ripe. That's an issue I'll figure out how to tackle when that road comes. For now though I can simply enjoy the flowers... that smell of rotting fish.