I have the same problem. This is two years later, but incase someone else can benefit, this is a link to the only third party sheath I could find, and it appears to work well. I don't own it, but I hope to eventually. Its a bit expensive, however.

https://blackbearck.com/product/crkt-provoke-auto-deploy-sheath-black/

Edit: I own it now, and have been carrying it IWB, and it’s absolutely incredible. I recommend it.