With the USB-OTG cable, you can use your virtual pitchbend by connecting your android device to your keyboard.

With MacunDroid 1.0.3 update now, Yamaha keyboards also support it.

For use;

MIDI IN section of your keyboard midi settings
Set it to

MIDI IN CH1: Upper 1
MIDI IN CH2: Upper 2
If there is,
MIDI IN CH3: Upper3