I want to create a Biome for my Mod, but I can't add to .topBlock or .fillerBlock my own Blocks. Has anyone a soulution for me?

You should keep your blockID under 256

Tanks. It works fine. It's a pity that the Forge Markers don't expand this range.

I'll let you in on a little trick I have been working on.  Essentially it is basically a terrain block that mimics other blocks.  For example you create a stone block that can be generated under the 256 ID.  You can then use conditionals based on the biome to change the texture and drop blocks, so theoretically you could make one stone block that uses a different texture based on conditions like height or biome.  So you could have 100 diff biomes, use the one stone "mimic" block that will change texture based on the biome it spawns in and have the stone drop your higher ID stone block when mined.  As far as I know you are not limited to the amount if conditional statements, and I havent tested out performance for something as crazy as 100 biomes, but so far on the smaller scale im working on I havent run into any problems.

That's a nice thought. Also Minemeister01 you can "thank" people for their answers when you helped them by clicking under the comment saying thanks. And its not a problem i made that mistake a while ago aswell.