Probably been answered before, but ...

I'm having trouble with the unit buttons. For one, I can't find the files where they are supposed to originate. Like this:

<Button>Art/Interface/Buttons/Units/Barbary_Corsair.dds</Button>

Now, where is this dds-file? It doesn't seem to be in the LoR folder or anywhere else.

All the art is packed; you must unpack the achilleszero and wolfshanze .fpk files useing packbuild. This is to improve performance, if the art wasn't packed it would take about 10 times as long for the engine to load. Civ4 also packs it's art for exactly the same reason.

Ah, I see.

But you could still add custom buttons outside this packed files, right? I did this for one unit, the Marine, but it only affects the unit buttons on the city bar, not the sevopedia or the unit buttons on the main screen (the map screen). Here, the standard Marine button shows up. Strange.