Black locust, right, Jojo?
I've not worked that stuff before. But I know someone who has and I'm pretty sure he boils his tips.
I've always heard that black locust is a lot like Osage but not sure myself. I know that Osage works well with dry heat and some oil.
Also try reducing the thickness if you haven't already. PatB told me once, to try and get the belly side to one ring before trying to bend it. Maybe someone with more experience with BL will chime in. Patrick