What??? You cant use AA with this scenery? Is this a joke?
You missed an "A". It's NOT AA (Antialiasing), it's AAA, which is an special feature available only on ATI cards, which means Adaptive Antialiasing, but it's not required at all having it enabled, in order to have AA, it's an independent setting and, apparently, there's a bug in one of the FSX Shaders which is not compatible with this setting. Or, there's a bug in the ATI driver, which doesn't like the FSX Shaders. Of course, since nobody used this kind of method in FSX before today, it never surfaced it so far.
In any case, AAA is not really a critical feature. I agree AA is, but the scenery doesn't have any problem with it.