Hi, winnaing,
I'm new to Arduino/RF too 
Lately I've been a bit busy with debugging some pieces of code and other things, but I'm planning to rewrite Livolo code since I've studied waveforms more carefully. You could wait a bit, or modify code yourself. I hope the following information would be of use in case you choose the latter.
The key is that command consists of unique remote ID (never changes) and key code (they appear to be fixed too, but change depending on key pressed). So you only need to change remote ID to get more keys, and there are plenty of these "virtual remotes" as each remote ID is 16 bit. Additionally, it is highly probable that Livolo switches can learn key codes other than I've discovered by recording remotes. So there could be even more remote ID and key code combinations.
But the thing is that changing remote ID (or key code) requires following strict rules, i.e.: pulses must interleave, that is high pulse should be always followed by low pulse; two short pulses are "0" and every single long pulse (apart from start) is "1" or vice versa, it doesn't matter as long as you code them right.