problem with 9920 and mechanical brake set up

I converted my Savage over to a brushless. I used a BK 9920 with a feigao 7xl motor. With this conversion I want to run the mechanical brake set up, but when I plug the brake servo in to the y-harness the controller will not program. I get the first beep then 5 seconds later I get the second beep then nothing, no double beep confermation.
If I plug the Controller right in to the reciever It programs no problem? Anyone had this problm before?
Thanks for the help