retaining mech brakes in 1/8 buggy conversions

[Sedri]

I've got a stumper of a question you you guys -

When I first set up my Kyosho Inferno, I used a Futaba "Magnum Junior" T2PEKA 2-Channel FM radio with a steering and a brake servo, using the Y-Connector to plug in a Warrior 9920BK. Set up this way, the Warrior was programmed for forward-only. "Reverse" on the transmitter throttle simply moved the throttle servo the other way, which applied the brakes.

Here's the Question - when I decided to run emf braking(motor braking), I removed the throttle servo and Y-connector and plugged the 9920BK directly into the receiver.

As per programming directions, I removed the red programming bridge, turned on the transmitter and reciever, plugged in the Lipo main battery and waited the "5 seconds" for the motor to beep to start programming.

NOthing! I tried a dozen times, then plugged in the y-connector again (with the servo plugged in and just lying on the table next to the car...

And instant, perfectly easy programming! Frustrated, I removed EVERYTHING from the car, dug out the cheapy Kyosho "perfex" 2-servo AM radio system that was originally in my Nitro Inferno, and pow, the 9920 programmed beautifully without the y-connector or throttle servo plugged in.

Why? Are there certain radio receivers that an electronic esc can't "recognize, or that ONLY work with a servo?

Right now I'm using the AM radio, which glitches from the brushless stuff, and my nice FM is sitting in a box, sniff. What to do?