I've been making some custom scenery around Sydney, and the YSSY airport using the latest terragear code from http://gitorious.org/fg/terragear.git
However I just sent a draft copy to someone else, and they are running FG V2.4, and they can't see any terrain at all. So I'm wondering if the tile format changed from V2.4 and that is why they can't see it, or if there is another problem. I'm running FG V2.11 (Git next) and it seems fine to me.
A copy of the scenery tiles is available at https://docs.google.com/file/d/0B-sIKXDCw9CIR0NVZTE3OXBmYm8/edit?usp=sharing if anyone wants to try it out.