help stitching panoramic images from mirror ball

I'm trying to create environmental based lighting using hdr images of a mirrored ball. I'm shooting a bracketed series of images from 2 different angles but am having a hard time stitching them together. I was hoping that someone else here is doing the same.

I've tried Photoshop, PTGui, Photomatix, none of them seem to successfully stitch them together. What is your workflow? Thanks