Since my electric car is not allowed to tow trailers, the ball of the trailer coupling was fitted with pins on the side (see Brink RMC): https://brink.eu/de-ch/anhaengerkupplungen/faq/welche-fahrradtraeger-passen-auf-die-brink-rmc-fahrradtraeger-transportloesung/ The Thule Onto is not "yet" listed in the compatibility list. Can this luggage box be mounted on a trailer coupling with lateral pins?