Have you grown this semi-tropical vine??? Any advice?
It looks beautiful; the seeds are hard to germinate so it shouldn't "escape."
"Escape"? Don't bet on it! Any member in the Fabaceae (Pea, bean) group has the potential to do so.
Hawai'i has three native Vigna spp.:
Vigna adenantha, with whitish and/or light purple flowers. Indigenous, but either very rare or now extinct in Hawaii. If it still grows here, I have no idea where.
Vigna marina, or nanea, a beach or inland species with bright yellow flowers; a common indigenous species and easy to grow from seed. Use as a ground cover. Available at Home Depot or Hui Ku Maoli Ola on O'ahu.
Vigna o-wahuensis, an endemic and endangered species but now available for cultivation. Grows in hot, dry locations. It has pale yellow flowers. Not as striking as V. marina, but very rare and worth growing. Hui Ku Maoli Ola (O'ahu) or Ho'olawa Farms (Maui) should have plants or seeds.
I would highly encourage anyone in Hawaii to grow these instead of introduced species.
I did a search on the speacies. I can see its very hard to resist. But to be safe we should avoid it. Even though it doesn't look very harmful (you can't really tell by looks anyhow). Unless there already is a local licensed grower who is selling or distributing plants of this species. However, in a way what deweydave said is kinda true. Of course it's all up to you.