The four-angled beans (what they are called in Malaysia) are called winged beans here. I bought them from both Baker Creek and Richters, and they are the day-neutral Japanese ones. They were growing in my greenhouse but died back in the fall before flowering. I can't remember when I sowed them, but wll try again this year.
What do you mean "the seeds are developing under the ground"? Are they rhizomatous?
I have two packets of Bambara beans, Burkina and Butterfly, both from Richters. I will grow them in the greenhouse also.
I have a long season here, but it seldom gets hot (maybe a couple of days per summer of 28 to 30 C. (80 to 85 F). My greenhouse doesn't get hot - I keep it well-ventilated - with the second-storey doors and skylights open. And evenings cool off quickly - we don't sit around outside at night.
Victoria, British Columbia, Canada a cool mediterranean climate - rainy winter, dry summer
No, I mean they literally grow UNDERGROUND, like peanuts. THAT'S why they are called Bambarra Groudnuts (and why the species name is subterrenea.
Those two are both long season ones, so you NEED a greenhouse. This also applies to the red ones Sacred Succulents has, and the brown ones Trade Winds Seeds has (I think the speckled day neutral ones were Baker Creek, but they don't seem to have them). I have the Malagasy ones Richter's had before they had the ones they have now (though I suspect these are in fact the exact same beans, as they look identical).