I followed the latter advice, moved the RCVR-AMP (AUD) function over to SAT and loaded the Technics code on to RCVR-AMP. Success: now the Sirius/JVC is on SAT and the Technics RCVR is on RCVR-AMP.

Now, I'll read up on the Advanced Codes to install the Technics Surround-Sound Processor to the remote, something I had not had the nerve to try before. Thanks to both of you for help and encouragement.