In A7, the smooth flag is supported in all editions, but was indeed not supported in A6 Extra - the manual was not up to date.

Static shadows on terrain are not supported. They will be supported in the next engine update, 7.77. The current version only supports static shadows on level geometry.

OK, thanks for the answers jcl.

I still got some problems with shadows, but now I think it is nothing do to with this topic. I will keep trying and post again here if I find anything new.