How can I get Duet Display working with my Hackingtosh successfully? It works fine on a MBP.

Duet Display works great on my iPad and my real Macbook

However on my Hackingtosh it only works in mirrored mode. When I try multimonitor mode I get a black screen no matter what resolution I set.

Specs here: Imgur

Anyone else managed to get Duet working with a Hack?