As The Titel Describes :P

From playing with it for a bit, it seems that carpenter's blocks remember the number and type of block they are using as camouflage, but certain slopes don't rotate properly. At the very least the interior and exterior oblique slopes are messing up for me most of the time. Carpenter's doors don't retain orientation (set by left clicking with the carpenter's hammer).
Chisel 2 stairs also rotate randomly, even if the structure is not rotated or mirrored.
Decocraft won't rotate with the structure, but if rotation is off it seems to work ok.

Most of these can be fixed by the authors themselves if they implement the rotate() functionality of Forge [properly]. If rotation is off and it still rotates it's probably weird block placement behavior - usually unideal implementation on their part too.

Anyway, I'm closing this as it's too general of an issue to be fixed properly. If you want to request generation compatibility for specific mods (and the exact problem they have) I can look into it more closely if they get their own issues.

FMP is currently on my 'won't support' list, since it does multiple things that divert from the normal MC API too much to support - see http://www.chickenbones.craftsaddle.org/Files/Other/ItemDevTool2.java.

If FMP is to be supported, someone has to fix FMP. A simple hack won't do here, I'm afraid.

What about the carpenter's blocks? What part exactly doesn't work? I could look into if it's fixable.