Depends on what you already have for pannier mounts, I would think. IIRC, some of the older Krauser mounts and/or another brand of mounts used tubing with brackets oriented horizontally to mate with those on your rear rack as shown. Some of the OEM BMW mounts had the rear rack integrated into the design as all of 1 piece, and some were bolt-on but with the bolt holes turned 90 degrees from those shown.
I suppose if you can weld you can modify anything to work if necessary.