Sounds like you are running a RetroPie based build.
In which case, you didn't add anything into Attract Mode, but instead added a launching image for that game. That's all controlled via RetroPie scripts...not Attract Mode or Emulation Station.
Once the runcommand.sh shell script is invoked, neither Emulation Station nor Attract Mode are operational. At that point, it's linux launching the emulator (and possibly using the xboxdrv and/or the joytokey python script).
Re-mapping controls to advance through the launching image isn't part of Attract Mode. You'll need to re-map it somehow using the xboxdrv or joytokey and/or something within the runcommand.sh script itself.
I think the displaying of those launching images (splash screens) is controlled from RetroPie's splash screens script.