I've looked at almost all the textures in FSXD. It seems that every texture apart from one in the effects folder, and oceaheightfield are all a new format. I looked at them through ImageTool, and it said failed to load, incorrect file format. DDS you can't load either.
My gc doesn't support DX9, so the water doesn't display correctly, but try putting in some of the FS9 addon water textures and see what it looks like. Could be cool.
Looks like ACES have created new formatting for the various game resources...