I see. Those buttons are actually joystick keys so keyboard event handler just drops them.
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Edit*
I checked the source code of sdl 2.0, if I'm not mistaken, sdl for android doesn't support joysticks but its own "Android accelerometer" device. It already maps dpad buttons to certain keyboard keys, for example, dpad directions as up/down/left/right, dpad center as select. Too bad xperia button circle is mapped as back, which will close the application.
If that is true, the only solution so far is force mapping those joystick buttons to other keycode, for example, joy button x as keyboard x, joy button 1 as 1, etc. This requires modifying sdl source code, which is OK but if a new official release is out we have to hack it again. That is why I said it is better to find a third party software.
http://www.addictivetips.com/mobile/remap-reassign-your-android-devices-keys-with-buttonremapper/
Another solution is using java code instead of sdl. The biggest problem is it doesn't have a proper map for key names.