If you wanted to get "fancy" you could hook an accessory decoder to the left/right function buttons on the turntable motor.
That's what I did for my Bascule bridge.
I imagine the Walther TT buttons are contact closure buttons. (But not certain) So a Transistor hooked to an accessory decoder would to the trick. The output for the decoder would be hooked to the Base leg on the transistor. (Typically marked "B") Connect the + input from one lead to the collector. And the other (ground or 0V) to the emmiter which goes back to turntable. IF the advance buttons are at track voltage DC (~14V), AND there is significant resistance across the button terminals, then you can probably safely hook the decoder output straight to the ground feed on the advance button.
P.S.: Be sure to use proper voltage transistors.
Make the accessory decoder use momentary function buttons on the cab. 1 Press = 1 track advance. F1 = Forward. F2 = Back.
Disclaimer: I have not done this. So the turntable MAY NOT operate this way. This is just a logical guess.
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Is it possible to operated the Walthers turntable via cab control? Mine works just fine but it would be pretty neat if it could be done.
Thanks