How to register a new Biome?

I have added mega taiga and mesa Biomes to my server...they both look amazing. But the thing is...I had to edit level/generators/normal/biomes/IcePlainBiome.php
...for mesa biomes because I can't figure out how to register a Biome, any help here?

Appears that it isn't possible unless you extend the Normal generator and override some functions like init(), then register it as a separate generator.

Unconfirmed, but this is what I'd do to save trouble.

Tried that already, didn't work
I think it's like the build height issue. It's the game..

Build height issue? We are talking about registering biomes. How would there be any relationship to the build height?

You cant increase the build height. Similarly biomes...i think you cant register any biomes other than what the game provides.

you can not register biome with custom ID but you can create biome with existing biome id but with different generation

Even if not, biomes are in this case purely server-side generation-related. As a matter of fact, you don't need to send the biome ID to the client. Why not simply send an existing ID but generate the chunks in the way you like?