535T Window Automation, 1992 Chevrolet Corvette

This is my first 535T install but I have experience with R/S and RKE so I'm not a complete n00bie. I have a 2101 RKE so I have a GWA input. The 92 Corvette is "Type B" windows in that both motor wires rest at +12V (with the IGN on). One wire is grounded to energize the motor. The 535T inputs respond to the (-) switch input. The 535T won't respond to the switch inputs when the GWA is grounded. So the switches can't activate the windows when the car is locked with the RKE. Ok, fine. But if the car is not locked with the RKE, the switches will operate the windows because the ground at the switches is always present. How do I DEactivate the switches with the key = OFF? Ie if the key is off, but the car is not locked, the switches can not trigger the 535T to ground. I can add a relay activated by B+ Ignition to ground the switches, and remove it with key = OFF, but there is nothing about this detail in the install guide. Is there something I don't know about the 535T in this regard? As always, thanks in advance for reading and any suggestions or guidance. Cheers.

I used a relay: #86 to the Delayed Accy Buss Pink wire at the driver window switch. #85 and #30 to Ground. #87 to the Common at each door switch. 535T set for (-) trigger switch inputs. I also inserted a diode in each window switch's gry/blk illumination wire, band towards switch. Otherwise, the bulb in the switch presents a ground path when the relay is open, and the windows still function with the key OFF. 2 diodes cured the problem.