I have fitted a few Kadee couplers, both body and truck mounted to circumvent various coupling issues on Fn3/1:20.3 scale stock. Mostly Bachmann. But not to your exotic Aster 1:22.5 beast. Although I do own an all metal Accucraft K-28 live steamer, but that is supplied with their own body mount knuckle couplers. What is your issue ? Have you tried contacing Kadee directly ? They usually know a convertion combination using their products that will work for specific makers loco/stock products. Max.