Cubic Chunks Height Limit

I've made a server with Cubic Chunks, but there's one big problem: We cannot build above the normal height limit, 256, despite being capable of doing so via commands. Is there a way to increase max-build-height in server.properties? Aternos doesn't let us access it directly for some reason, as Options menu does not include some things like max-build-height.

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Servers

For servers you need to set forceCubicChunks option to true in cubicchunks.cfg config file.

Note: don't forget to change max build height in server.properties if it's from vanilla."
From the OpenCubicChunks page. Have you tried raising it above 256 with CubicChunks installed?