Wiring harness or pigtail for HAES 4 X 40 Amp
 

I have a spare Becker CR210 radio/head unit that I want to install along with a HAES 4 X 40 Amp (which I got from a Boxster) into a 914. I can get a wiring harness from Becker radio in NJ with the proper radio end plug terminating into 2 female RCA jacks which would work with most aftermarket amps (according to Becker). I can't figure out how to connect it to the HAES amp that I own. I don't have any wiring for the amp, and it seems the smaller of the two jacks on the amp is the one that would go to the radio/head unit and the larger jack to the speakers. So that would mean that I need a wiring harness with a unigue HAES plug on one end terminating into 2 male RCA jacks on the other. Is this correct? Does such a thing exist? Does anybody know of a wiring harness that would connect both radio and amp directly? Or how or where to get 2 pigtails (one for radio and one for amp) and splice them together? I can't find anything on internet about parts or wiring harnesses for HAES. Local stereo install shop (Car Toys) are clueless. Can anybody help? Thanks.