#if (CONFIG_KEYPAD == SANSA_E200_PAD)
#define PICTUREFLOW_COMBO_KEY BUTTON_REC
#endif
.
.
.
int main(void) {
...
switch(button)
...
        case PICTUREFLOW_COMBO_KEY:
            DEBUGF("Test\n");
            if (config.zoom < 300)
                config.zoom = config.zoom + 1;
            render_all_slides;
            break;
        default:
            if (rb->default_event_handler_ex(button, cleanup, NULL)
                == SYS_USB_CONNECTED)
                return PLUGIN_USB_CONNECTED;
            break;
        }
...
}