I do this but with collards. Collards are milder so no need for a heavy frost to make them taste good. The shade from the beens will actually let you plant them a month sooner. That way the OCT rains will produce tonnage instead of germination. When the beans die out the greens take over. I just till it all under after the greens seed in early spring. Take a soil sample, amend and have never had to replant the beens. The collards come back in the spring as well but die out in July. So they have to be reseeded.
Doing it this way gives me a lot of organic matter to put back in the soil. So far I have gotten away with it 6 years without crop rotation. As a bonus it gives them a good food supply in early spring with the collard sprouts when times are hard.
Blessings