Adding trunk or luggage rack to Valkyrie Motor Trike

[Yakimavalk]

Looking for ideas on how to add a luggage rack or trunk to my Valk trike...I had a GIVI trunk on the back of it before triking but will not fit now because it won't clear the hatch door or if I try to put a luggage rock on, same results.

Edit: My avatar is showing no backrest but actually I do have one because when I took the pic it wasn't quite finished with the install.