Givi monolock base

I have a givi monolock base from my scooter and am looking to fit to my gs1150. I can't seem to find the proper fitting kit to mount onto the rack. My baseplate is as below

http://www.brandedbiker.co.uk/Givi-Luggage/Givi-MM-Aluminium-Monolock-Plate-7758

I had fitted this to my pillion seat of my r1 with a bit of plywood but thought there was something more suitable for the gs?