Well, as I mentioned previously, I used the Givi sidecases without a topcase. I simply took a piece of flat steel stock and filed a couple of notches into it. The notches fit between the grab rail bolts and have enough "bite" to make a secure hold. Attached the steel stock to the Givi rack by means of a pipe clamp. If it sounds like Southern Engineering, it is, but it looks fine all painted up and holds securely. I could post a pic or two if anyone is just dying to duplicate my rigged system. Otherwise, I'm too lazy.