Well, here's a quick update, just in case anyone is interested in manufacturer/vendor experiences:
I have sent a mail to CS of both HighwayHawk and ChromeAndLeatherPlus (where I bought the set) over a week ago; both of them took some time answering. Chrome And Leather Plus was pretty much nice but not overly helpful, telling me they can only sell me another full kit, although they did offer me a 20% discount. However, Highway Hawk sent me a roughly 6-word e-mail. In Dutch. It translated as "We can't help you. We're sorry."
Bitter? no, I'm not. Mildly surprised, perhaps... C&L was not one I was expecting to be helpful - after all, they're just a re-seller.
Anyway... I'm still looking to trade, as per my original cost, or buy the replacement part I need...